DHCP Options

DHCP provides a framework for passing configuration information to hosts on a TCP/IP network. Configuration
parameters and other control information are carried in tagged data items that are stored in the options field
of the DHCP message. The data items themselves are also called options.
This appendix contains DHCP options and BOOTP vendor extensions from RFC 2132, and includes the
validation type for each option, as indicated in Table 10: DHCPv4 Options by Number , on page 34.
This appendix also contains the standard Microsoft client options and several tables displaying the options
sorted by categories.
• Option Descriptions, on page 1
• Option Tables, on page 33

Option Descriptions
The following sections describe the DHCP options in detail:
• RFC 1497 Vendor Extensions, on page 1
• IP Layer Parameters Per Host, on page 4
• IP Layer Parameters Per Interface, on page 6
• Link Layer Parameters Per Interface, on page 7
• TCP Parameters, on page 8
• Application and Service Parameters, on page 9
• DHCPv4 Extension Options, on page 16
• DHCPv6 Options, on page 22
• Microsoft Client Options, on page 21
• Options by Number, on page 33
• Options by Cisco Prime Network Registrar Name, on page 40
• Option Validation Types, on page 52

RFC 1497 Vendor Extensions

The table below lists the vendor extensions as defined in RFC 1497.

DHCP Options
1
DHCP Options
DHCP Options

Table 1: RFC 1497 Vendor Extension Options

Option Name No. Length Description

Pad 0 1 octet Causes the subsequent

fields to align on word
boundaries.

End 255 1 octet End of valid information

in the vendor field.
Subsequent octets should
be filled with the Pad
options.

Subnet Mask 1 4 octets Client subnet mask, as per

RFC 950. If both the
Subnet Mask and the
Router option are
specified in a DHCP
reply, the Subnet Mask
option must be first.

Time Offset 2 4 octets Offset of the client subnet,

in seconds, from
Universal Time (UT). The
offset is expressed as a
twos-complement 32-bit
integer. A positive offset
indicates a location east of
the zero meridian and a
negative offset indicates a
location west of the zero
meridian.

Router 3 4 octets minimum; List of IP addresses for

multiples of 4 routers on the client
subnet. Routers should be
in order of preference.

Time Server 4 4 octets minimum; List of RFC 868

multiples of 4 compliant time servers
available to the client.
Servers should be in order
of preference.

Name Server Option 5 4 octets minimum; List of IEN 116 name

multiples of 4 servers available to the
client. Servers should be
in order of preference.

DHCP Options
2
DHCP Options
DHCP Options

Option Name No. Length Description

Domain Name Server 6 4 octets minimum; List of Domain Name

multiples of 4 System (STD 13, RFC
1035) name servers
available to the client.
Servers should be in order
of preference.

Log Server 7 4 octets minimum; List of MIT-LCS UDP log

multiples of 4 servers available to the
client. Servers should be
in order of preference.

Cookie Server 8 4 octets minimum; List of RFC

multiples of 4 865-compliant cookie
servers available to the
client. Servers should be
in order of preference.

LPR Server 9 4 octets minimum; List of RFC

multiples of 4 1179-compliant line
printer servers available
to the client. Servers
should be in order of
preference.

Impress Server 10 4 octets minimum; List of Imagen Impress

multiples of 4 servers available to the
client. Servers should be
in order of preference.

Resource Location Server 11 4 octets minimum; List of RFC

multiples of 4 887-compliant resource
location servers available
to the client. Servers
should be in order of
preference.

Host Name 12 1 octet minimum Name of the client. The

name may or may not be
qualified with the local
domain name. See RFC
1035 for the character set
restrictions.

Boot File Size 13 2 octets Number of 512-octet

blocks in the default boot
file.

DHCP Options
3
DHCP Options
IP Layer Parameters Per Host

Option Name No. Length Description

Merit Dump File 14 1 octet minimum Path name of a file to

which the client core
image should be placed in
the event the client
crashes. The path is
formatted as a character
string consisting of
characters from the NVT
ASCII character set.

Domain Name 15 1 octet minimum Domain name that the

client should use when
resolving hostnames
through the Domain Name
System.

Swap Server 16 4 octets IP address of the client

swap server.

Root Path 17 1 octet minimum Path name that contains

the client root disk. The
path is formatted as a
character string consisting
of characters from the
NVT ASCII character set.

Extensions Path 18 1 octet minimum Uses a string to specify a

file, retrievable through
TFTP. The file contains
information that can be
interpreted in the same
way as the 64-octet
vendor-extension field
within the BOOTP
response, with these
exceptions: the length of
the file is unconstrained,
and all references to
instances of this option in
the file are ignored.

IP Layer Parameters Per Host

The table below lists the options that affect the operation of the IP layer on a per-host basis.

DHCP Options
4
DHCP Options
DHCP Options

Table 2: IP Layer Parameters Per Host Options

Option Name No. Length Description

IP Forwarding 19 1 octet Specifies whether the

Enable/Disable client should configure its
IP layer for packet
forwarding. Values:
0=disable; 1=enable

Non-Local Source 20 1 octet Specifies whether the

Routing Enable/Disable client should configure its
IP layer to allow
forwarding of datagrams
with non-local source
routes. Values: 0=disable;
1=enable

Policy Filter 21 8 octets minimum; Policy filters for non-local

multiples of 8 source routing. The filters
consist of a list of IP
addresses and masks that
specify destination/mask
pairs with which to filter
incoming source routes.
Any source-routed
datagram whose next-hop
address does not match
one of the filters should
be discarded by the client.

Maximum Datagram 22 2 octets Maximum size datagram

Reassembly Size that the client should be
prepared to reassemble.
Value: 576 minimum

Default IP Time-to-live 23 1 octet Default TTL that the

client should use on
outgoing datagrams.
Values: 1 to 255

Path MTU Aging Timeout 24 4 octets Timeout (in seconds) to

use when aging Path
MTU values (defined in
RFC 1191).

DHCP Options
5
DHCP Options
IP Layer Parameters Per Interface

Option Name No. Length Description

Path MTU Plateau Table 25 2 octets minimum; Table of MTU sizes to use
multiples of 2 when performing Path
MTU Discovery as
defined in RFC 1191. The
table is formatted as a list
of 16-bit unsigned
integers, ordered from
smallest to largest. Value:
68 minimum

IP Layer Parameters Per Interface

The table below lists the options that affect the operation of the IP layer on a per-interface basis. A client can
issue multiple requests, one per interface, to configure interfaces with their specific parameters.

Table 3: IP Layer Parameters Per Interface Options

Option Name No. Length Description

Interface MTU 26 2 octets MTU to use on this

interface.The minimum
legal value for the MTU
is 68.

All Subnets are Local 27 1 octet Specifies whether or not

the client can assume that
all subnets of the IP
network to which the
client is connected use the
same MTU as the subnet
of that network to which
the client is directly
connected. Values: 1=all
subnets share same MTU;
0=some
directly-connected subnets
can have smaller MTUs

Broadcast Address 28 4 octets Broadcast address in use

on the client subnet.

Perform Mask Discovery 29 1 octet Specifies whether or not

the client should perform
subnet mask discovery
using ICMP. Values:
0=disable; 1=enable

DHCP Options
6
DHCP Options
Link Layer Parameters Per Interface

Option Name No. Length Description

Mask Supplier 30 1 octet Specifies whether or not

the client should respond
to subnet mask requests
using ICMP. Values:
0=do not respond;
1=respond

Perform Router Discovery 31 1 octet Specifies whether or not

the client should solicit
routers using the Router
Discovery mechanism
defined in RFC 1256.
Values: 0=disable;
1=enable

Router Solicitation 32 4 octets Address to which the

Address client should transmit
router solicitation
requests.

Static Route 33 8 octets minimum; List of static routes that

multiples of 8 the client should install in
its routing cache. If
multiple routes to the
same destination are
specified, they are in
descending order of
priority. The routes
consist of a list of IP
address pairs. The first
address is the destination
address, and the second
address is the router for
the destination. The
default route (0.0.0.0) is
an illegal destination for
a static route.

Link Layer Parameters Per Interface

The table below lists the options that affect the operation of the data link layer on a per-interface basis.

DHCP Options
7
DHCP Options
TCP Parameters

Table 4: Link Layer Parameters Per Interface Options

Option Name No. Length Description

Trailer Encapsulation 34 1 octet Specifies whether or not

the client should negotiate
the use of trailers (RFC
893) when using the ARP
protocol. Values: 0=do
not use; 1=use

ARP Cache Timeout 35 4 octets Timeout in seconds for

ARP cache entries.

Ethernet Encapsulation 36 1 octet Specifies whether or not

the client should use
Ethernet Version 2 (RFC
894) or IEEE 802.3 (RFC
1042) encapsulation if the
interface is an Ethernet.
Value: 0=use RFC 894
encapsulation; 1=use RFC
1042 encapsulation

TCP Parameters
The table below lists the options that affect the operation of the TCP layer on a per-interface basis.

Table 5: TCP Parameter Options

Option Name No. Length Description

TCP Default TTL 37 1 octet Default TTL that the

client should use when
sending TCP segments.
Value: minimum 1

DHCP Options
8
DHCP Options
Application and Service Parameters

Option Name No. Length Description

TCP Keepalive Interval 38 4 octets Interval (in seconds) that

the client TCP should wait
before sending a keepalive
message on a TCP
connection. The time is
specified as a 32-bit
unsigned integer. A value
of zero indicates that the
client should not generate
keepalive messages on
connections unless
specifically requested by
an application. Value:
32-bit unsigned; 0=do not
generate keepalive
messages unless
specifically requested.

TCP Keepalive Garbage 39 1 octet Specifies the whether or

not the client should send
TCP keep-alive messages
with an octet of garbage
for compatibility with
older implementations.
Values: 0=do not send;
1=send

Application and Service Parameters

The table below lists some miscellaneous options used to configure miscellaneous applications and services.

Table 6: Application and Service Parameter Options

Option Name No. Length Description

Network Information 40 1 octet minimum Name of the client NIS

Service (NIS) Domain domain. The domain is
formatted as a character
string consisting of
characters from the NVT
ASCII character set.

Network Information 41 4 octets minimum; List of IP addresses

Service (NIS) Servers multiples of 4 indicating NIS servers
available to the client.
Servers should be in order
of preference.

DHCP Options
9
DHCP Options
DHCP Options

Option Name No. Length Description

Network Time Protocol 42 4 octets minimum; List of IP addresses

Servers multiples of 4 indicating NTP servers
that are available to the
client. Servers should be
in order of preference.

DHCP Options
10
DHCP Options
DHCP Options

Option Name No. Length Description

Vendor-Specific 43 1 octet minimum

Information

DHCP Options
11
DHCP Options
DHCP Options

Option Name No. Length Description

This option is used by
clients and servers to
exchange vendor-specific
information. The
information is an opaque
object of n octets,
presumably interpreted by
vendor-specific code on
the clients and servers.
The definition of this
information is vendor
specific. The vendor is
indicated in the
dhcp-class-identifier
option. Servers not
equipped to interpret the
vendor-specific
information sent by a
client must ignore it
(although it can be
reported). Clients that do
not receive desired
vendor-specific
information should make
an attempt to operate
without it, although they
can do so (and announce
they are doing so) in a
degraded mode.
If a vendor potentially
encodes more than one
item of information in this
option, then the vendor
should encode the option
using encapsulated
vendor-specific options as
described here.
The encapsulated
vendor-specific options
field should be encoded as
a sequence of code,
length, and value fields of
identical syntax to the
DHCP options field with
these exceptions:
• There should not be
a magic cookie field
in the encapsulated

DHCP Options
12
DHCP Options
DHCP Options

Option Name No. Length Description

vendor-specific
extensions field.
• Codes other than 0 or
255 can be redefined
by the vendor within
the encapsulated
vendor-specific
extensions field, but
should conform to
the tag-length-value
syntax defined in
section 2.
Code 255 (END), if
present, signifies the end
of the encapsulated
vendor extensions, not the
end of the vendor
extensions field.
If the code 255 is not
present, then the end of
the enclosing
vendor-specific
information field is taken
as the end of the
encapsulated
vendor-specific extensions
field.

NetBIOS over TCP/IP 44 4 octets minimum; List of RFC 1001/1002

Name Server multiples of 4 NBNS name servers in
order of preference.

NetBIOS over TCP/IP 45 4 octets minimum; List of RFC 1001/1002

Datagram Distribution multiples of 4 NBDD servers in order of
Server preference.

DHCP Options
13
DHCP Options
DHCP Options

Option Name No. Length Description

NetBIOS over TCP/IP 46 1 octet Allows NetBIOS over

Node Type TCP/IP client, which are
configured as described in
RFC 1001/1002. Values:
Single hexadecimal octet
that identifies the client
type:
• 0x1=B-node
(broadcast node)
• 0x2=P-node
(point-to-point node)
• 0x4=M-node (mixed
node)
• 0x8=H-node

NetBIOS over TCP/IP 47 1 octet minimum NetBIOS over TCP/IP

Scope scope parameter for the
client as specified in RFC
1001/1002.

X Window System Font 48 4 octets minimum; List of X Window System

Server multiples of 4 Font servers available to
the client. Servers should
be in order of preference.

X Window System 49 4 octets minimum; List of IP addresses of

Display Manager multiples of 4 systems that are running
the X Window System
Display Manager and are
available to the client.
Addresses should be in
order of preference.

Network Information 64 1 octet minimum Name of the client NIS+

Service (NIS+) Domain domain. The domain is
formatted as a character
string consisting of
characters from the NVT
ASCII character set.

Network Information 65 4 octets minimum; List of IP addresses

Service (NIS+) Servers multiples of 4 indicating NIS+ servers
available to the client.
Servers should be in order
of preference.

DHCP Options
14
DHCP Options
DHCP Options

Option Name No. Length Description

Mobile IP Home Agent 68 0 octet minimum; List of IP addresses

multiples of 4; expected, indicating mobile IP home
4 octets containing a agents available to the
single home agent address client. Agents should be
in order of preference.
Value: 32-bit address;
0=no home agents
available

Simple Mail Transport 69 4 octets minimum; List of SMTP servers

Protocol (SMTP) Server multiples of 4 available to the client.
Servers should be in order
of preference.

Post Office Protocol 70 4 octets minimum; List of POP3 servers

(POP3) Server multiples of 4 available to the client.
Servers should be in order
of preference.

Network News Transport 71 4 octets minimum; List of NNTP servers

Protocol (NNTP) Server multiples of 4 available to the client.
Servers should be in order
of preference.

Default World Wide Web 72 4 octets minimum; List of World Wide Web
(WWW) Server multiples of 4 (WWW) servers available
to the client. Servers
should be in order of
preference.

Default Finger Server 73 4 octets minimum; List of Finger servers

multiples of 4 available to the client.
Servers should be in order
of preference.

Default Internet Relay 74 4 octets minimum; List of IRC servers

Chat (IRC) Server multiples of 4 available to the client.
Servers should be in order
of preference.

StreetTalk Server 75 4 octets minimum; List of StreetTalk servers

multiples of 4 available to the client.
Servers should be in order
of preference.

StreetTalk Directory 76 4 octets minimum; List of STDA servers

Assistance (STDA) Server multiples of 4 available to the client.
Servers should be in order
of preference.

DHCP Options
15
DHCP Options
DHCPv4 Extension Options

DHCPv4 Extension Options

The table below lists the DHCPv4 extension options.

Table 7: DHCPv4 Extensions

Option Name No. Length Description

Requested IP Address 50 4 octets Used in a client request

(DHCPDISCOVER) to
allow the client to request
that a particular IP address
be assigned.

IP Address Lease Time 51 4 octets Used in a client request

(DHCPDISCOVER or
DHCPREQUEST) to
allow the client to request
a lease time for the IP
address. In a server reply
(DHCPOFFER), a DHCP
server uses this option to
specify the lease time it is
willing to offer. Value:
seconds, as 32-bit
unsigned integer

Option Overload 52 1 octet Indicates that the DHCP

sname or file fields are
being overloaded by using
them to carry DHCP
options. A DHCP server
inserts this option if the
returned parameters will
exceed the usual space
allotted for options. If this
option is present, the
client interprets the
specified additional fields
after it concludes
interpretation of the
standard option fields.
Values: 1=file field is
used to hold options;
2=sname field is used to
hold options; 3=both
fields are used to hold
options

DHCP Options
16
DHCP Options
DHCP Options

Option Name No. Length Description

DHCP Message Type 53 1 octet Used to convey the type

of DHCP message. The
preset value is 1
(DHCPDISCOVER).
Values:
1=DHCPDISCOVER;
2=DHCPOFFER;
3=DHCPREQUEST;
4=DHCPDECLINE;
5=DHCPACK;
6=DHCPNAK;
7=DHCPRELEASE;
8=DHCPINFORM;
13=LEASEQUERY

Server Identifier 54 4 octets Used in DHCPOFFER

and DHCPREQUEST
messages, and can
optionally be included in
the DHCPACK and
DHCPNAK messages.
DHCP servers include this
option in the
DHCPOFFER in order to
allow the client to
distinguish between lease
offers. DHCP clients use
the contents of the server
identifier field as the
destination address for
any DHCP messages
unicast to the DHCP
server. DHCP clients also
indicate which of several
lease offers is being
accepted by including this
option in a
DHCPREQUEST
message. The identifier is
the IP address of the
selected server.

DHCP Options
17
DHCP Options
DHCP Options

Option Name No. Length Description

Parameter Request List 55 1 octet minimum Used by a DHCP client to

request values for
specified configuration
parameters. The list of
requested parameters is
specified as n octets,
where each octet is a valid
DHCP option code as
defined in this document.
The client can list the
options in order of
preference. The DHCP
server does not have to
return the options in the
requested order, but must
try to insert the options in
the order that the client
requested.

Message 56 1 octet minimum Used by a DHCP server

to provide an error
message to a DHCP client
in a DHCPNAK message
in the event of a failure. A
client can use this option
in a DHCPDECLINE
message to indicate why
the client declined the
offered parameters. The
message consists of n
octets of NVT ASCII text,
which the client can
display on an available
output device.

Maximum DHCP 57 2 octets Maximum-length DHCP

Message Size message that a server is
willing to accept. The
length is specified as an
unsigned 16-bit integer. A
client can use the
maximum DHCP message
size option in
DHCPDISCOVER or
DHCPREQUEST
messages, but should not
use the option in
DHCPDECLINE
messages. Value: 576
minimum

DHCP Options
18
DHCP Options
DHCP Options

Option Name No. Length Description

Renewal (T1) Time Value 58 4 octets Time interval from

address assignment until
the client transitions to
RENEWING state. Value:
seconds, as 32-bit
unsigned integer

Rebinding (T2) Time 59 4 octets Time interval from

Value address assignment until
the client transitions to
REBINDING state.
Value: seconds, as 32-bit
unsigned integer

Vendor Class Identifier 60 1 octet minimum Used by DHCP clients to

optionally identify the
vendor type and
configuration of a DHCP
client. The information is
a string of n octets,
interpreted by servers.
Vendors can choose to
define specific vendor
class identifiers to convey
particular configuration or
other identification
information about a client.
For example, the identifier
can encode the client
hardware configuration.
Servers not equipped to
interpret the class-specific
information sent by a
client must ignore it
(although it can be
reported). Servers that
respond should only use
option 43 to return the
vendor-specific
information to the client.

DHCP Options
19
DHCP Options
DHCP Options

Option Name No. Length Description

Client-Identifier 61 2 octets minimum Used by DHCP clients to

specify their unique
identifier. DHCP servers
use this value to index
their database of address
bindings. This value is
expected to be unique for
all clients in an
administrative domain.
DHCP servers should treat
identifiers as opaque
objects. The client
identifier can consist of
type-value pairs similar to
the htype /chaddr fields.
For instance, it can consist
of a hardware type and
hardware address. In this
case, the type field should
be one of the ARP
hardware types defined in
STD2. A hardware type
of 0 (zero) should be used
when the value field
contains an identifier
other than a hardware
address (for example, a
fully qualified domain
name).
For correct identification
of clients, each
client-identifier must be
unique among the
client-identifiers used on
the subnet to which the
client is attached. Vendors
and system administrators
are responsible for
choosing client-identifiers
that meet this requirement
for uniqueness.

TFTP Server name 66 1 octet minimum Identifies a TFTP server

when the sname field in
the DHCP header has
been used for DHCP
options.

DHCP Options
20
DHCP Options
Microsoft Client Options

Option Name No. Length Description

Bootfile name 67 1 octet minimum Identifies a bootfile when

the file field is the DHCP
header that has been used
for DHCP options.

Relay Agent Information 82 Identifies the DHCP relay

agent information (see
RFC 3046)

iSNS 83 14 bytes minimum Identifies the Internet

Storage Name Service
(see RFC 4174)

BCMCS Controller 88 Variable List of Broadcast and

Domain Multicast Service
(BCMCS) controller
domains (see RFC 4280)

BCMCS Address 89 4 octets minimum List of IP addresses for

the BCMCS controller
(see RFC 4280)

Lease Query Client Last 91 4 octets Time of the most recent

Transaction Time access of the client
sending a
DHCPLEASEQUERY
(see RFC 4388).

Lease Query Associated 92 4 octets minimum All IP addresses

IP Addresses associated with the client
specified in a particular
DHCPLEASEQUERY
message (see RFC 4388).

Microsoft Client Options

The table below lists the standard Microsoft client options.

Table 8: Microsoft DHCP Client Options

Option Name No. Description

dhcp-lease-time 51 14 days

domain-name 15 A domain name such as cisco.com

domain-name-servers 6 IP address of the name servers

netbios-name-servers 44 WINS server address

DHCP Options
21
DHCP Options
DHCPv6 Options

Option Name No. Description

netbios-node-type 46 Identifies the NetBIOS client type;

note that Cisco Prime Network
Registrar displays a warning if it is
not present

routers 3 IP address of the router for this

subnet

DHCPv6 Options
The table below lists the DHCPv6 options, along with their defined data types. All the option packets include
at least an option length (option-len) and a variable length data field. There can also be additional parameter
settings, as described in the table. Many of these options are described in RFC 3315.

Table 9: DHCPv6 Options

Cisco Prime Network Registrar No. Description

Name (Type)

client-identifier 1 DUID identifying a client between

a client and a server.
AT_BLOB

server-identifier 2 DUID identifying a server between

a client and a server.
AT_BLOB

ia-na 3 Nontemporary Addresses option

with the associated parameters and
AT_BLOB
addresses. Parameters are the
unique ID, time the client contacts
the addresses in the IA to extend
the lifetime, and time the client
contacts any available server to
extend the lifetime of the addresses.

ia-ta 4 Temporary Addresses option with

the associated parameters and
AT_BLOB
addresses.

iaaddr 5 IPv6 addresses associated with an

IA_NA or IA_TA. (The IAADRR
AT_BLOB
must be encapsulated in the options
field of an IA_NA or IA_TA
option.) The IAADDR option
includes preferred and valid
lifetime fields, and the options field
that encapsulates the options
specific to this address.

DHCP Options
22
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

oro 6 Option Request option (ORO) that

identifies a list of options in a
AT_SHORT
message between a client and a
server. A client can include this
option in a Solicit, Request, Renew,
Rebind, Confirm, or
Information-request message to
inform the server about options the
client wants from the server. A
server can include this option in a
Reconfigure message to indicate
which option updates the client
should request.

preference 7 A server sends this option to a

client to affect what server the
AT_INT8
client selects.

elapsed-time 8 A client sends this option to a

server to indicate how long the
AT_SHORT
client has been trying to complete
a message exchange.

relay-message 9 DHCP message in a Relay-forward

or Relay-reply message.
AT_BLOB

auth 11 Authenticates the identity and

contents of a DHCP message. The
AT_BLOB
parameters are the authentication
protocol, the authentication
algorithm, the replay detection
method (RDM), and the
authentication information.

server-unicast 12 The server sends this option to a

client to indicate that the client can
AT_IP6ADDR
unicast messages to the server.

status-code 13 Returns a status indication related

to the DHCP message or option in
AT_BLOB
which it appears. The parameters
are the status code and status
message.

rapid-commit 14 Signals use of the two-message

exchange for address assignment.
AT_ZEROSIZE

DHCP Options
23
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

user-class 15 Clients use this option to identify

the type or category of user or
AT_TYPECNT
applications it represents. A zero
type count value field followed by
user data (as a blob).

vendor-class 16 Clients use this option to identify

the vendor that manufactured the
AT_VENDOR_CLASS
hardware on which they are
running.

vendor-opts 17 Clients and servers use this option

to exchange vendor-specific
AT_VENDOR_OPTS
information. The enterprise ID for
the CableLabs vendor is 4491; the
suboptions for CableLabs are listed
in Table 4.

interface-id 18 Relay agents use this option to

identify the interface on which the
AT_BLOB
client message is received.

reconfigure-message 19 The server includes this in a

Reconfigure message to indicate
AT_INT8
whether the client should respond
with a Renew or
Information-request message.

reconfigure-accept 20 Clients use this option to announce

to the server whether the client is
AT_ZEROSIZE
willing to accept Reconfigure
messages.

sip-servers-name 21 Domain names of the SIP outbound

proxy servers for the client. See
AT_DNSNAME
RFC 3319.

sip-servers-address 22 IPv6 addresses of the SIP outbound

proxy servers for the client.
AT_IP6ADDR

dns-servers 23 IPv6 addresses of DNS recursive

name servers.
AT_IP6ADDR

domain-list 24 Domain names in the domain

search list.
AT_DNSNAME

DHCP Options
24
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

ia-pd 25 IPv6 prefix delegation identity

association and its associated
AT_BLOB
parameters and prefixes. Parameters
are the unique ID, time the client
contacts the addresses in the IA to
extend the lifetime, and time the
client contacts any available server
to extend the lifetime of the
addresses.

iaprefix 26 IPv6 prefixes associated with an

IA_PD. The prefix must be
AT_BLOB
encapsulated in the options field of
an IA_PD option. Parameters are
the valid and preferred lifetimes,
prefix length, and the prefix.

nis-servers 27 List of IPv6 addresses of Network

Information Service (NIS) servers
AT_IP6ADDR
available to the client (see RFC
3898).

nisp-servers 28 List of IPv6 addresses of NIS+

servers available to the client.
AT_IP6ADDR

nis-domain-name 29 Conveys the NIS domain name to

the client.
AT_DNSNAME

nisp-domain-name 30 Conveys the NIS+ domain name to

the client.
AT_DNSNAME

sntp-servers 31 List of Simple Network Time

Protocol (SNTP) servers available
AT_IP6ADDR
to the client (see RFC 4075).

info-refresh-time 32 Sets an upper bound for how long

a client should wait before
AT_TIME
refreshing DHCPv6 information
(see RFC 4242).

bcmcs-server-d 33 List of BCMCS controller domains

(see RFC 4280).
AT_DNSNAME

bcmcs-server-a 34 List of IPv6 addresses for the

Broadcast and Multicast Service
AT_IP6ADDR
(BCMCS) controller (see RFC
4280).

DHCP Options
25
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

geoconf-civic 36 DHCP civic addresses

configuration.
AT_BLOB

remote-id 37 Relay agents that terminate

switched or permanent circuits can
AT_BLOB
add this option to identify remote
hosts (see RFC 4649).

relay-agent-subscriber-id 38 Allows assignment and activation

of subscriber-specific actions (see
AT_BLOB
RFC 4580).

client-fqdn 39 DHCP client FQDN.

AT_BLOB

pana-agent 40 Carries a list of 32-bit (binary) IPv4

addresses indicating PANA
AT_IP6ADDR
Authentication Agents (PAAs)
available to the PANA client (PaC)

new-posix-timezone 41 POSIX time zone, for example,

EST5EDT4,
AT_NSTRING
M3.2.0/02:00,M11.1.0/02:00.

new-tzdb-timezone 42 POSIX time zone database name,

for example, Europe/Zurich.
AT_NSTRING

ero 43 Relay agent Echo Request option

to inform the server of the list of
AT_SHORT
relay agent options to echo back.

lq-query 44 Used only in a LEASEQUERY

message; identifies the query being
AT_BLOB
performed. The option includes the
query type, link-address (or 0::0),
and options to provide data needed
for the query.

client-data 45 Encapsulates the data for a single

client on a single link in a
AT_CONTAINER6
LEASEQUERY-REPLY message.

clt-time 46 Client last transaction time

encapsulated in the client-data
AT_TIME
option; identifies how long ago the
server last communicated with the
client (in seconds).

DHCP Options
26
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

lq-relay-data 47 Used only in a

LEASEQUERY-REPLY message;
AT_BLOB
provides the relay agent data used
when the client last communicated
with the server.

lq-client-links 48 Used only in a

LEASEQUERY-REPLY message;
AT_IP6ADDR
identifies the links on which the
client has one or more bindings. It
is used in reply to a query when no
link-address was specified and the
client is found to be on more than
one link.

mip6-hnidf 49 Defines the Home Network ID

FQDN option.
AT_DNSNAME

mip6-vdinf 50 Defines the Visited Home Network

Information option.
AT_CONTAINER6

lost-server 51 A DHCPv6 client will request a

LoST server domain name in an
AT_DNSNAME
Options Request Option (ORO)
(see RFC 3315).
This option contains a single
domain name and must contain
precisely one root label.

capwap-ac-v6 52 Carries a list of 128-bit (binary)

IPv6 addresses indicating one or
AT_IP6ADDR
more Control and Provisioning of
Wireless Access Point (CAPWAP)
Access Controllers (ACs) available
to the Wireless Termination Point
(WTP) (see RFC 5417).

relay-id 53 A DHCPv6 server MAY associate

Relay-ID options from
AT_BLOB
Relay-Forward messages it
processes with prefix delegations
and/or lease bindings that result.

mos-address 54 Mobility Sever (MoS) IPv6

Address for DHCP v4.
AT_IP6ADDR

DHCP Options
27
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

mos-fqdn 55 Mobility Sever (MoS) Domain

Name List for DHCPv6.
AT_BLOB

ntp-server 56 Serves as a container for server

location information related to one
AT_BLOB
Network Time Protocol (NTP)
server or Simple Network Time
Protocol (SNTP) server. This
option can appear multiple times in
a DHCPv6 message. Each instance
of this option is to be considered by
the NTP client or SNTP client as a
server to include in its
configuration.
The option itself does not contain
any value. Instead, it contains one
or several suboptions that carry
NTP server or SNTP server
location.

access-domain 57 Defines the domain name

associated with the access network.
AT_DNSNAME
This option contains a single
domain name and, as such, must
contain precisely one root label.

sip-ua-cs-domains 58 Defines the list of domain names

in the Session Initiation Protocol
AT_DNSNAME
(SIP) User Agent Configuration
Service Domains.

bootfile-url 59 Informs the client about a URL to

a boot file.
AT_NSTRING

bootfile-param 60 Sent by the server to the client. It

consists of multiple UTF-8 (see
AT_TYPECNT
RFC3629) strings for specifying
parameters for the boot file.

client-arch-type 61 Provides parity with the Client

System Architecture Type option
AT_SHORT
(option 93) defined for DHCPv4.

nii 62 Provides parity with the Client

Network Interface Identifier option
AT_BLOB
(option 94) defined for DHCPv4.

DHCP Options
28
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

geoloc 63 Specifies the coordinate-based

geographic location of the client,
AT_BLOB
to be provided by the server.

aftr-name 64 Defines a fully qualified domain

name of the AFTR tunnel endpoint.
AT_DNSNAME

erp-local-domain-name 65 Contains the name of the local ERP

domain.
AT_DNSNAME

rsoo 66 Encapsulates whatever options the

relay agent wishes to provide to the
AT_CONTAINER6
DHCPv6 server.

pd-exclude 67 Used to exclude exactly one prefix

from a delegated prefix.
AT_BLOB

vpn-id 68 Used to identify a VPN.

AT_BLOB

mip6-idinf 69 Used by relay agents and DHCP

servers to provide information
AT_CONTAINER6
about the home network identified.

mip6-udinf 70 Provides information about a home

network specified by the DHCP
AT_CONTAINER6
server administrator.

mip6-hnp 71 Defines the prefix for a home

network.
AT_BLOB

mip6-haa 72 Used by DHCP servers and relay

agents to specify the home agent IP
AT_IP6ADDR
address.

mip6-haf 73 Specifies the Home Agent FQDN

to look up one or more A or AAAA
AT_DNSNAME
records containing IPv4 or IPv6
addresses for the home agent, as
needed.

rdnss-selection 74 Informs resolvers which RDNSS

can be contacted when initiating
AT_BLOB
forward or reverse DNS lookup
procedures.

DHCP Options
29
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

krb-principal-name 75 Sent by the client to the DHCPv6

server, which uses it to select a
AT_BLOB
specific set of configuration
parameters, either for a client or for
a Kerberos application server.

krb-realm-name 76 Specifies to a DHCPv6 server

which realm the client wants to
AT_NSTRING
access.

krb-default-realm-name 77 Specifies a default realm name for

the Kerberos system (clients and
AT_NSTRING
Kerberos application servers).

krb-kdc 78 Provides configuration information

about a KDC.
AT_BLOB

client-linklayer-address 79 Indicates the client link layer

address.
AT_BLOB

link-address 80 Indicates to the server the link on

which the client is located.
AT_IP6ADDR

radius 81 Provides a mechanism to exchange

authorization and identification
AT_BLOB
information between the DHCPv6
relay agent and DHCPv6 server.

sol-max-rt 82 Overrides the default value of

sol-max-rt.
AT_TIME

inf-max-rt 83 Overrides the default value of

inf-max-rt.
AT_TIME

addrsel 84 Provides the policy table and some

other configuration parameters.
AT_BLOB

addrsel-table 85 Provides the Address Selection

Policy Table options.
AT_BLOB

v6-pcp-server 86 Configures a list of IPv6 addresses

of a PCP server. This option
AT_IP6ADDR
supports only single instance (RFC
7291).

DHCP Options
30
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

dhcpv4-msg 87 Carries a DHCPv4 message that is

sent by the client or the server.
AT_BLOB
Such messages exclude any IP or
UDP headers.

dhcp4-o-dhcp6-server 88 Carries a list of DHCP 4o6 servers'

IPv6 addresses that the client
AT_IP6ADDR
should contact to obtain IPv4
configuration.

s46-rule 89 Conveys the Basic Mapping Rule

(BMR) and Forwarding Mapping
AT_BLOB
Rule (FMR).

s46-br 90 Conveys the the IPv6 address of the

Border Relay.
AT_IP6ADDR

s46-dmr 91 Conveys values for the Default

Mapping Rule (DMR).

s46-v4v6bind 92 Specifies the full or shared IPv4

address of the CE. The IPv6 prefix
AT_BLOB
field is used by the CE to identify
the correct prefix to use for the
tunnel source.

s46-portparams 93 Specifies optional port set

information that MAY be provided
AT_BLOB
to CEs.

s46-cont-mape 94 Specifies the container used to

group all rules and optional port
AT_CONTAINER6
parameters for a specified domain
(Softwire46 MAP-E domain).

s46-cont-mapt 95 Specifies the container used to

group all rules and optional port
AT_CONTAINER6
parameters for a specified domain
(Softwire46 MAP-T domain).

s46-cont-lw 96 Specifies the container used to

group all rules and optional port
AT_CONTAINER6
parameters for a specified domain
(Softwire46 Lightweight 4over6
domain).

4rd 97 Indicates the DHCPv6 option for

4rd (IPv4 Residual Deployment).
AT_CONTAINER6

DHCP Options
31
DHCP Options
DHCP Options

Cisco Prime Network Registrar No. Description

Name (Type)

4rd-map-rule 98 Indicates the Mapping-Rule

Parameters of 4rd domains.
AT_BLOB

4rd-non-map-rule 99 Indicates the Non-Mapping-Rule

Parameters of 4rd domains.
AT_BLOB

lq-base-time 100 Current time the message was

created to be sent by the DHCPv6
AT_INT
server to the requestor of the Active
or Bulk Leasequery if the requestor
asked for the same in an Active or
Bulk Leasequery request (RFC
7653).

lq-start-time 101 Specifies a query start time to the

DHCPv6 server (RFC 7653).
AT_INT

lq-end-time 102 Specifies a query end time to the

DHCPv6 server (RFC 7653).
AT_INT

captive-portal 103 Informs the client that it is behind

a captive portal and provides the
AT_NSTRING
URI to access an authentication
page (RFC 7710).

mpl-parameters 104 Provides a means to distribute a

configuration of an MPL Domain
AT_BLOB
or a default value for all MPL
Domains (a wildcard) within the
network managed by the DHCP
server (RFC 7774).

ani-att 105 Used for exchanging the type of

access technology the client uses to
AT_BLOB
attach to the network (RFC 7839).

ani-network-name 106 Name of the access network to

which the mobile node is attached
AT_NSTRING
(RFC 7839).

ani-ap-name 107 Name of the access point (physical

device name) to which the mobile
AT_NSTRING
node is attached (RFC 7839).

ani-ap-bssid 108 48-bit Basic SSSID (BSSID) of the

access point to which the mobile
AT_BLOB
node is attached (RFC 7839).

DHCP Options
32
DHCP Options
Option Tables

Cisco Prime Network Registrar No. Description

Name (Type)

ani-operator-id 109 Variable-length Private Enterprise

Number (PEN) encoded in a
AT_BLOB
network byte order (RFC 7839).

ani-operator-realm 110 Realm of the operator (RFC 7839).

AT_NSTRING

s46-priority 111 Conveys a priority order of IPv4

service continuity mechanisms
AT_SHORT
(RFC 8026).

prefix64 113 Conveys the IPv6 prefix(es) to be

used (for example, by an mB4) to
AT_BLOB
synthesize IPv4-embedded IPv6
addresses (RFC 8115).

ipv6-address-andsf 143 Allows the mobile node (MN) to

locate an ANDSF server (RFC
AT_IP6ADDR
7839).

Option Tables
The following tables display the DHCP options in various ways. They show the options sorted numerically,
by Cisco Prime Network Registrar name, and by category.
DHCP options have a prescribed format and allowed values for their option parameters. Table 10: DHCPv4
Options by Number , on page 34 lists each DHCP option and parameter type (in the Validation column). The
parameter formats and allowed values come from the DHCP and Internet RFCs. All the DHCP options appear,
but clients control only some, and the CLI only others.

Options by Number
The table below shows the DHCPv4 options sorted by option number, and includes the validation type. (See
Table 12: Validation Types , on page 52 for details on the option validation types found in the Validation
column.) A 0+ in the Comments column means a repeat count of zero or more occurrences, 1+ means one or
more occurrences, 2n means multiple occurrences in multiples of 2. Comments also indicate whether the
option includes suboptions, and, if so, how many.

Tip For the syntax for adding more complex option data values for suboptions, see Adding Complex Values for
Suboptions.

DHCP Options
33
DHCP Options
DHCP Options

Table 10: DHCPv4 Options by Number

No. Cisco Prime Protocol Name Validation Comments

Network Registrar
Name

0 pad Pad AT_NOLEN

1 subnet-mask Subnet Mask AT_IPADDR

2 time-offset Time Offset AT_STIME Replaced by tz-

options (RFC 4833)

3 routers Router AT_IPADDR 1+

4 time-servers Time Server AT_IPADDR 1+

5 name-servers Name Server AT_IPADDR 1+

6 domain-name-servers Domain Server AT_IPADDR 1+

7 log-servers Log Server AT_IPADDR 1+

8 cookie-servers Quotes Server AT_IPADDR 1+

9 lpr-servers LPR Server AT_IPADDR 1+

10 impress-servers Impress Server AT_IPADDR 1+

11 resource-location-servers RLP Server AT_IPADDR 1+

12 host-name Host Name AT_NSTRING

13 boot-size Boot File Size AT_SHORT

14 merit-dump Merit Dump File AT_NSTRING

15 domain-name Domain Name AT_NSTRING

16 swap-server Swap Server AT_IPADDR

17 root-path Root Path AT_NSTRING

18 extensions-path Extension File AT_NSTRING

19 ip-forwarding Forward On/Off AT_BOOL

20 non-local-source-routing SrcRte On/Off AT_BOOL

21 policy-filters Policy Filter AT_IPADDR 2n

22 max-dgram-reassembly Maximum DG AT_SHORT

Assembly

23 default-ip-ttl Default IP TTL AT_RANGEBYTE

24 path-mtu-aging-timeout MTU Timeout AT_TIME

DHCP Options
34
DHCP Options
DHCP Options

No. Cisco Prime Protocol Name Validation Comments

Network Registrar
Name

25 path-mtu-plateau-tables MTU Plateau AT_RANGESHORT 1+

26 interface-mtu MTU Interface AT_RANGESHORT

27 all-subnets-local MTU Subnet AT_BOOL

28 broadcast-address Broadcast Address AT_IPADDR

29 perform-mask-discovery Mask Discovery AT_BOOL

30 mask-supplier Mask Supplier AT_BOOL

31 router-discovery Router Discovery AT_BOOL

32 router-solicitation-address Router Request AT_IPADDR

33 static-routes Static Route AT_IPADDR 2n

34 trailer-encapsulation Trailers AT_BOOL

35 arp-cache-timeout ARP Timeout AT_TIME

36 ieee802.3-encapsulation Ethernet AT_BOOL

37 default-tcp-ttl Default TCP TTL AT_RANGEBYTE

38 tcp-keepalive-interval Keepalive Time AT_TIME

39 tcp-keepalive-garbage Keepalive Data AT_BOOL

40 nis-domain NIS Domain AT_NSTRING

41 nis-servers NIS Servers AT_IPADDR 1+

42 ntp-servers NTP Servers AT_IPADDR 1+

43 vendor-encapsulated- Vendor Specific AT_BLOB NM

options

44 netbios-name-servers NetBIOS Name AT_IPADDR 1+

Server

45 netbios-dd-servers NetBIOS AT_IPADDR 1+

Distribution Server

46 netbios-node-type NetBIOS Node AT_RANGEBYTE

Type

47 netbios-scope NetBIOS Scope AT_NSTRING

48 font-servers X Window Font AT_IPADDR 1+

DHCP Options
35
DHCP Options
DHCP Options

No. Cisco Prime Protocol Name Validation Comments

Network Registrar
Name

49 x-display-managers X Window Manager AT_IPADDR 1+

50 dhcp-requested-address Address Request AT_IPADDR

51 dhcp-lease-time Address Time AT_TIME NM

52 dhcp-option-overload Overload AT_OVERLOAD

53 dhcp-message-type DHCP Message AT_MESSAGE NM (See the DHCP

Type Message Type
option in Table 7:
DHCPv4 Extensions
, on page 16)

54 dhcp-server-identifier DHCP Server ID AT_IPADDR

55 dhcp-parameter-request- Parameter List AT_INT8 0+

list

56 dhcp-message DHCP Message AT_NSTRING NM

57 dhcp-max-message-size DHCP Maximum AT_SHORT NM

Message Size

58 dhcp-renewal-time Renewing Time AT_TIME NM

59 dhcp-rebinding-time Rebinding Time AT_TIME NM

60 dhcp-class-identifier Class Identifier AT_NSTRING

61 dhcp-client-identifier Client Identifier AT_BLOB

62 netwareip-domain NetWare/IP Domain AT_NSTRING

63 netwareip-information NetWare/IP Option AT_BLOB

64 nis+-domain NIS Domain Name AT_NSTRING

65 nis+-servers NIS Server Address AT_IPADDR 1+

66 tftp-server TFTP Server Name AT_NSTRING

67 boot-file Bootfile Name AT_NSTRING

68 mobile-ip-home-agents Mobile IP Home AT_IPADDR 0+

Agent

69 smtp-servers SMTP Server AT_IPADDR 1+

70 pop3-servers POP3 Server AT_IPADDR 1+

71 nntp-servers NNTP Server AT_IPADDR 1+

DHCP Options
36
DHCP Options
DHCP Options

No. Cisco Prime Protocol Name Validation Comments

Network Registrar
Name

72 www-servers WWW Server AT_IPADDR 1+

73 finger-servers Finger Server AT_IPADDR 1+

74 irc-servers IRC Server AT_IPADDR 1+

75 streettalk-servers StreetTalk Server AT_IPADDR 1+

76 streettalk-directory- STDA Server AT_IPADDR 1+

assistance-servers

77 dhcp-user-class-id User Class ID AT_TYPECNT Suboptions (2)

78 slp-directory-agent Service Location AT_BLOB Suboptions (2)

Protocol Directory
Agent

79 slp-service-scope SLP Service Scope AT_BLOB Suboptions (2)

80 rapid-commit Rapid Commit AT_ZEROSIZE

81 client-fqdn Client FQDN AT_BLOB Suboptions (4)

82 relay-agent-info Relay Agent AT_BLOB For suboptions, see

Information Table 3

83 iSNS Internet Storage AT_BLOB Suboptions (7)

Name Service
(RFC4174)

85 nds-servers NDS Servers AT_IPADDR 1+

86 nds-tree NDS Tree Name AT_NSTRING

87 nds-context NDS Context AT_NSTRING

88 bcmcs-servers-d BCMCS Controller AT_DNSNAME 1+

Domain (RFC 4280)

89 bcmcs-servers-a BCMCS Address AT_IPADDR 1+

90 authentication Authentication AT_BLOB Suboptions (5)

91 lq- Lease Query Client AT_TIME

client-last-transaction- Last Transaction
time Time

92 lq- associated-ip Lease Query AT_IPADDR 1+

Associated IP
Addresses

DHCP Options
37
DHCP Options
DHCP Options

No. Cisco Prime Protocol Name Validation Comments

Network Registrar
Name

93 pxe-client-arch AT_SHORT

94 pxe-client-network-id AT_BLOB Suboptions (2)

95 ldap-url AT_NSTRING

97 pxe-client-machine-id AT_BLOB Suboptions (2)

98 user-auth AT_NSTRING

99 geoconf-civic Civic Addresses AT_BLOB

Configuration

100 posix-timezone IEEE 1003.1 String AT_NSTRING

101 tzdb-timezone Time Zone Database AT_NSTRING

112 netinfo-parent-server-addr AT_IPADDR

113 netinfo-parent-server-tag AT_NSTRING

114 initial-url AT_NSTRING

116 auto-configure Autoconfiguration AT_RANGEBYTE

117 name-service-search Name Service AT_SHORT 1+

Search

118 subnet-selection Subnet Selection AT_IPADDR

119 domain-search Domain Search AT_DNSNAME 1+

120 sip-servers SIP Servers AT_BLOB Suboptions (2)

121 classless-static-route Classless Static AT_BLOB

Route

122 cablelabs-client- CableLabs Client AT_BLOB Suboptions (10) (see

configuration Configuration the Table 3)

123 geo-conf GeoConf Option AT_BLOB

124 v-i-vendor-class Vendor-Identifying AT_VENDOR_CLASS NM

Vendor Class

125 v-i-vendor-opts Vendor-Identifying AT_VENDOR_OPTS See also the

Vendor-Specific cablelabs-125
Info suboptions in Table
3

128 mcns-security-server -- AT_IPADDR

DHCP Options
38
DHCP Options
DHCP Options

No. Cisco Prime Protocol Name Validation Comments

Network Registrar
Name

136 pana-agent AT_IPADDR 1+

137 lost-server AT_DNSNAME

138 capwap-ac-v4 AT_IPADDR 1+

139 mos-address AT_BLOB Suboptions (3)

0+

140 mos-fqdn AT_BLOB Suboptions (3)

0+

141 sip-ua-cs-domains AT_DNSNAME 0+

142 andsf-v4 Access Network AT_IPADDR

Discovery and
Selection Function

144 geoloc Geospatial Location AT_BLOB

with Uncertainty

145 forcerenew-nonce-capable Forcerenew Nonce AT_INT8 1+

Authentication

146 rdnss-selection RDNSS Selection AT_BLOB Suboptions (4)

150 tftp-server-address TFTP AT_IPADDR 1+

151 status-code AT_BLOB Suboptions (2)

152 base-time AT_DATE

153 start-time-of-state AT_TIME

154 query-start-time AT_DATE

155 query-end-time AT_DATE

156 dhcp-state AT_INT8

157 data-source AT_INT8

158 v4-pcp-server Port Control AT_BLOB Suboptions (2)

159 v4-portparams AT_BLOB Suboptions (3)

160 captive-portal DHCP AT_NSTRING

Captive-Portal

161 cisco-leased-ip Cisco AT_IPADDR

DHCP Options
39
DHCP Options
Options by Cisco Prime Network Registrar Name

No. Cisco Prime Protocol Name Validation Comments

Network Registrar
Name

162 cisco-client-requested- Cisco AT_NSTRING

host-name

163 cisco-client-last- Cisco AT_INT

transaction-time

185 vpn-id VPN Identifier AT_BLOB NM: Suboptions (2)

209 pxelinux-config-file AT_NSTRING

210 pxelinux-path-prefix AT_NSTRING

211 pxelinux-reboot-time AT_TIME

212 6rd AT_BLOB Suboptions (4)

213 access-domain AT_NSTRING

220 subnet-alloc Subnet Allocation AT_TIME Suboptions (5)

221 cisco-vpn-id Cisco VPN AT_NSTRING Suboptions (2)

Identifier

251 cisco-auto-configure Cisco AT_RANGEBYTE

Autoconfiguration

255 end End AT_NOLEN NM

Options by Cisco Prime Network Registrar Name

The table below lists the DHCP options by Cisco Prime Network Registrar name. (For each option validation
type, cross-reference it by number to Table 10: DHCPv4 Options by Number , on page 34 and check the
Validation column.)

Table 11: DHCP Options by Cisco Prime Network Registrar Name

Cisco Prime Network No. Option Name Category

Registrar Name

4rd 97 IPv4 Residual DHCPv6

Deployment via IPv6
(4rd)

4rd-map-rule 98 4rd Map Rule DHCPv6

4rd-non-map-rule 99 4rd Non Map Rule DHCPv6

DHCP Options
40
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

6rd 212 IPv6 Rapid Deployment DHCPv4

on IPv4 Infrastructures
(6rd)

access-domain 213 Access Network Domain DHCPv4

Name

access-domain 57 Access Network Domain DHCPv6

Name

addrsel 84 Address Selection DHCPv6

addrsel-table 85 Address Selection Policy DHCPv6

Table

aftr-name 64 AFTR tunnel endpoint DHCPv6

domain name

all-subnets-local 27 All Subnets Are Local Interface

andsf-v4 142 ANDSF IPv4 Address for DHCPv4

DHCPv4

ani-ap-bssid 108 DHCPv6 DHCPv6

Access-Point-BSSID

ani-ap-name 107 DHCPv6 DHCPv6

Access-Point-Name

ani-att 105 DHCPv6 DHCPv6

Access-Technology-Type

ani-network-name 106 DHCPv6 Network-Name DHCPv6

ani-operator-id 109 DHCPv6 DHCPv6

Operator-Identifier

ani-operator-realm 110 DHCPv6 Operator-Realm DHCPv6

arp-cache-timeout 35 ARP Cache Timeout Interface

associated-ip 92 Lease Query Associated DHCPv4

IP

auth 11 Authentication DHCPv6

authentication 90 Authentication DHCPv4

auto-configure 116 Auto-Configuration DHCPv4

base-time 152 base-time DHCPv4

DHCP Options
41
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

bcmcs-server-a 34 BCMCS Address v6 DHCPv6

bcmcs-server-d 33 BCMCS Controller DHCPv6

Domain v6

bcmcs-servers-a 89 BCMCS Address DHCPv4

bcmcs-servers-d 88 BCMCS Controller DHCPv4

Domain

boot-file 67 Bootfile Name BOOTP

boot-size 13 Boot File Size BOOTP

bootfile-param 60 Boot File Parameters DHCPv6

bootfile-url 59 Boot File Uniform DHCPv6

Resource Locator (URL)

broadcast-address 28 Broadcast Address Interface

cablelabs-client-configuration 122 CableLabs Client DHCPv4

Configuration

captive-portal 103 Captive-Portal DHCPv6 DHCPv6

captive-portal 160 Captive-Portal DHCPv4 DHCPv4

capwap-ac-v4 138 CAPWAP AC DHCPv4

capwap-ac-v6 52 CAPWAP AC DHCPv6

cisco-auto-configure 251 Cisco Autoconfiguration DHCPv4

cisco-client-last-transaction-time 163 Cisco Client Last DHCPv4

Transaction Time

cisco-client-requested-host-name 162 Cisco Client Requested DHCPv4

Host Name

cisco-leased-ip 161 Cisco Leased IP Address DHCPv4

cisco-vpn-id 221 Cisco VPN Identifier DHCPv4

classless-static-route 121 Classless Static Route DHCPv4

client-arch-type 61 Client System DHCPv6

Architecture Type

client-data 45 Leasequery Reply Client DHCPv6

Data

client-fqdn 81 DHCP Client FQDN DHCPv4

DHCP Options
42
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

client-fqdn 39 DHCP Client FQDN DHCPv6

client-identifier 1 Client Identifier DHCPv6

client-last-transaction-time 91 Leasequery Client Last DHCPv4

Transaction Time

client-linklayer-address 79 DHCPv6 Client DHCPv6

Link-Layer Address

clt-time 46 Leasequery Client Last DHCPv6

Transaction Time

cookie-servers 8 Cookie Server BOOTP

data-source 157 data-source DHCPv4

default-ip-ttl 23 Default IP Time-to-Live Host IP

default-tcp-ttl 37 TCP Default TTL Interface

dhcp-class-identifier 60 Vendor Class Identifier DHCPv4

dhcp-client-identifier 61 Client-Identifier Basic

dhcp-lease-time 51 IP Address Lease Time Lease Information, MS

DHCP Client

dhcp-max-message-size 57 Maximum DHCP DHCPv4

Message Size

dhcp-message 56 Message DHCPv4

dhcp-message-type 53 DHCP Message Type DHCPv4

dhcp-option-overload 52 Option Overload DHCPv4

dhcp-parameter-request-list 55 Parameter Request List DHCPv4

dhcp-rebinding-time 59 Rebinding (T2) Time Lease Information, MS

Value DHCP Client

dhcp-renewal-time 58 Renewing (T1) Time Lease Information, MS

Value DHCP Client

dhcp-requested-address 50 Requested IP Address DHCPv4

dhcp-server-identifier 54 Server Identifier DHCPv4

dhcp-state 156 State of IP Address DHCPv4

dhcp-user-class-id 77 User Class ID DHCPv4

DHCP Options
43
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

dhcp4-o-dhcp6-server 88 DHCP 4o6 Server DHCPv6

Address

dhcpv4-msg 87 DHCPv4 Message DHCPv6

dns-servers 23 DNS Recursive Name DHCPv6

Server

domain-list 24 Domain Search List DHCPv6

domain-name 15 Domain Name Basic, MS DHCP Client

domain-name-servers 6 Domain Name Server Basic, MS DHCP Client

domain-search 119 Domain Search DHCPv4

elapsed-time 8 Elapsed Time DHCPv6

end 255 End DHCPv4

ero 43 Relay Agent Echo DHCPv6

Request Option

erp-local-domain-name 65 Local ERP domain name DHCPv6

extensions-path 18 Extensions Path BOOTP

finger-servers 73 Finger Server Servers

font-servers 48 X Window System Font Servers

Server

forcerenew-nonce-capable 145 Forcerenew Nonce DHCPv4

Authentication

geo-conf 123 GeoConf DHCPv4

geoconf-civic 99 Civic Addresses DHCPv4

Configuration

geoconf-civic 36 Civic Addresses DHCPv6

Configuration

geoloc 63 Geolocation DHCPv6

geoloc 144 Geospatial Location with DHCPv4

Uncertainty

host-name 12 Host Name Basic

ia-na 3 Identity Association for DHCPv6

Nontemporary Addresses

DHCP Options
44
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

ia-pd 25 Prefix Delegation DHCPv6

ia-ta 4 Identity Association for DHCPv6

Temporary Addresses

iaaddr 5 IA Address DHCPv6

iaprefix 26 IA Prefix DHCPv6

ieee802.3-encapsulation 36 Ethernet Encapsulation Interface

impress-servers 10 Impress Server BOOTP

inf-max-rt 83 Max Information-Request DHCPv6

Timeout

info-refresh-time 32 Information Refresh Time DHCPv6

initial-url 114 URL DHCPv4

interface-id 18 Interface Identifier DHCPv6

interface-mtu 26 Interface MTU Interface

ip-forwarding 19 IP Forwarding Host IP

Enable/Disable

ipv6-address-andsf 143 ANDSF IPv6 Address DHCPv6

irc-servers 74 IRC Server Servers

iSNS 83 iSNS DHCPv4

krb-default-realm-name 77 Kerberos Default Realm DHCPv6

Name

krb-kdc 78 Kerberos KDC DHCPv6

krb-principal-name 75 Kerberos Principal Name DHCPv6

krb-realm-name 76 Kerberos Realm Name DHCPv6

ldap-url 95 Lightweight Directory DHCPv4

Access Protocol (LDAP)
Servers

link-address 80 Link Address DHCPv6

log-servers 7 Log Server Servers

lost-server 51 Location-to-Service DHCPv6

Translation (LoST) Server
DHCPv6

DHCP Options
45
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

lost-server 137 LoST Server DHCPv4 DHCPv4

lpr-servers 9 LPR Server Servers

lq-associated-ip 92 Leasequery Associated IP DHCPv4

Address

lq-base-time 100 Leasequery Base Time DHCPv6

lq-client-last-transaction-time 91 Leasequery Client DHCPv4

Transaction Time

lq-client-links 48 Leasequery Client Link DHCPv6

Reply

lq-end-time 102 Leasequery End Time DHCPv6

lq-query 44 Leasequery DHCPv6

lq-relay-data 47 Leasequery Relay Agent DHCPv6

Reply

lq-start-time 101 Leasequery Start Time DHCPv6

mask-supplier 30 Mask Supplier Interface

max-dgram-reassembly 22 Maximum Datagram Host IP

Reassembly Size

mcns-security-server 128 -- Servers

merit-dump 14 Merit Dump File DHCPv4

mip6-haa 72 MIPv6 Home Agent DHCPv6

Address

mip6-haf 73 MIPv6 Home Agent DHCPv6

FQDN

mip6-hnidf 49 MIPv6 Home Network ID DHCPv6

FQDN

mip6-hnp 71 MIPv6 Home Network DHCPv6

Prefix

mip6-idinf 69 MIPv6 Identified Home DHCPv6

Network Information

mip6-udinf 70 MIPv6 Unrestricted Home DHCPv6

Network Information

DHCP Options
46
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

mip6-vdinf 50 MIPv6 Visited Home DHCPv6

Network Information

mobile-ip-home-agents 68 Mobile IP Home Agent Servers

mos-address 139 MoS IPv4 Address DHCPv4

mos-address 54 MoS IPv6 Address DHCPv6

mos-fqdn 140 MoS Domain Name List DHCPv4

mos-fqdn 55 MoS Domain Name List DHCPv6

mpl-parameters 104 MPL Parameters DHCPv6

name-servers 5 Name Server BOOTP

name-service-search 117 Name Service Search DHCPv4

nds-context 87 NDS Context NetWare Client

nds-servers 85 NDS Servers NetWare Client

nds-tree 86 NDS Tree Name NetWare Client

netbios-dd-servers 45 NetBIOS over TCP/IP WINS/NetBIOS

Datagram Distribution
Server

netbios-name-servers 44 NetBIOS over TCP/IP WINS/NetBIOS, MS

Name Server DHCP Client

netbios-node-type 46 NetBIOS over TCP/IP WINS/NetBIOS, MS

Node Type DHCP Client

netbios-scope 47 NetBIOS over TCP/IP WINS/NetBIOS, MS

Scope DHCP Client

netinfo-parent-server-addr 112 NetInfo Parent Server DHCPv4

Address

netinfo-parent-server-tag 113 NetInfo Parent Server Tag DHCPv4

netwareip-domain 62 NetWare/IP Domain NetWare Client

Name

netwareip-information 63 NetWare/IP Information NetWare Client

new-posix-timezone 41 POSIX time zone string DHCPv6

new-tzdb-timezone 42 POSIX time zone DHCPv6

database name

DHCP Options
47
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

nii 62 Client Network Interface DHCPv6

Identifier

nis+-domain 64 NIS+ Domain Servers

nis+-servers 65 Network Information Servers

Service (NIS+) Servers

nis-domain 40 NIS Domain Servers

nis-domain-name 29 NIS Domain Name DHCPv6

nis-servers 41 Network Information Servers

Service (NIS) Servers

nis-servers 27 NIS Servers DHCPv6

nisp-domain-name 30 NIS+ Domain Name DHCPv6

nisp-servers 28 NIS+ Servers DHCPv6

nntp-servers 71 NNTP Server Servers

non-local-source-routing 20 Non-Local Source Host IP

Routing

ntp-server 56 Message DHCPv6

ntp-servers 42 NTP Servers Servers

option-time 8 Option Time DHCPv6

oro 6 Option Request Option DHCPv6

pad 0 Pad DHCPv4

pana-agent 40 PANA Authentication DHCPv6

Agent DHCPv6

pana-agent 136 PANA Authentication DHCPv4

Agent DHCPv4

path-mtu-aging-timeout 24 Path MTU Aging Timeout Host IP

path-mtu-plateau-tables 25 Path MTU Plateau Table Host IP

pd-exclude 67 Prefix Exclude DHCPv6

perform-mask-discovery 29 Perform Mask Discovery Interface

policy-filters 21 Policy Filter Host IP

pop3-servers 70 POP3 Server Servers

DHCP Options
48
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

posix-timezone 100 IEEE 1003.1 String DHCPv4

preference 7 Preference DHCPv6

prefix64 113 Prefix64 DHCPv6

pxe-client-arch 93 Client System DHCPv4

Architecture Type

pxe-client-machine-id 97 Client Machine Identifier DHCPv4

pxe-client-network-id 94 Client Network Interface DHCPv4

Identifier

pxelinux-config-file 209 Configuration File DHCPv4

pxelinux-path-prefix 210 Path Prefix DHCPv4

pxelinux-reboot-time 211 Reboot Time DHCPv4

query-end-time 155 query-end-time DHCPv4

query-start-time 154 query-start-time DHCPv4

radius 81 DHCPv6 RADIUS DHCPv6

rapid-commit 80 Rapid Commit DHCPv4

rapid-commit 14 Rapid Commit DHCPv6

rdnss-selection 74 RDNSS Selection DHCPv6

DHCPv6

rdnss-selection 146 RDNSS Selection DHCPv4

DHCPv4

reconfigure-accept 20 Reconfigure Accept DHCPv6

reconfigure-message 19 Reconfigure Message DHCPv6

relay-agent-info 82 DHCP Relay Agent DHCPv4

Information

relay-agent-subscriber-id 38 Relay Agent Subscriber DHCPv6

ID

relay-id 53 Relay ID DHCPv6

relay-message 9 Relay Message DHCPv6

remote-id 37 Relay Agent Remote ID DHCPv6

resource-location-servers 11 Resource Location Server BOOTP

DHCP Options
49
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

root-path 17 Root Path BOOTP

router-discovery 31 Perform Router Discovery Interface

router-solicitation-address 32 Router Solicitation Interface

Address

routers 3 Router Basic, MS DHCP Client

rsoo 66 Relay-Supplied Options DHCPv6

s46-br 90 Softwire46 (S46) Border DHCPv6

Relay (BR)

s46-cont-lw 96 S46 Lightweight 4over6 DHCPv6

Container

s46-cont-mape 94 S46 MAP-E Container DHCPv6

s46-cont-mapt 95 S46 MAP-T Container DHCPv6

s46-dmr 91 S46 Default Mapping DHCPv6

Rule (DMR)

s46-portparams 93 S46 Port Parameters DHCPv6

s46-priority 111 S46 Priority DHCPv6

s46-rule 89 S46 Rule DHCPv6

s46-v4v6bind 92 S46 IPv4/IPv6 Address DHCPv6

Binding

server-identifier 2 DHCPv6 Server Identifier DHCPv6

server-unicast 12 Server Unicast DHCPv6

sip-servers 120 SIP Servers DHCPv4

sip-servers-name 21 SIP Servers Domain DHCPv6

Name List

sip-servers-address 22 SIP Servers IPv6 Address DHCPv6

List

sip-ua-cs-domains 141 SIP UA Configuration DHCPv4

Service Domains

sip-ua-cs-domains 58 SIP User Agent DHCPv6

Configuration Service
Domains

DHCP Options
50
DHCP Options
DHCP Options

Cisco Prime Network No. Option Name Category

Registrar Name

sip-ua-cs-domains 141 SIP User Agent DHCPv4

Configuration Service
Domains

slp-directory-agent 78 SLP Directory Agent DHCPv4

slp-service-scope 79 SLP Service Scope DHCPv4

smtp-servers 69 SMTP Server Servers

sntp-servers 31 SNTP Configuration DHCPv6

sol-max-rt 82 SOL_MAX_RT DHCPv6

start-time-of-state 153 start-time-of-state DHCPv4

static-routes 33 Static Route Interface

status-code 13 Status Code DHCPv6

status-code 151 Status Code DHCPv4

streettalk-directory- 76 STDA Server Servers

assistance-servers

streettalk-servers 75 StreetTalk Server Servers

subnet-alloc 220 Subnet Allocation DHCPv4

subnet-mask 1 Subnet Mask Basic

subnet-selection 118 Subnet Selection DHCPv4

swap-server 16 Swap Server BOOTP

tcp-keepalive-garbage 39 TCP Keepalive Garbage Interface

tcp-keepalive-interval 38 TCP Keepalive Interval Interface

tftp-server 66 TFTP Server Name Servers

tftp-server-address 150 TFTP Server Address Servers

time-offset 2 Time Offset BOOTP

time-servers 4 Time Server BOOTP

trailer-encapsulation 34 Trailer Encapsulation Interface

tzdb-timezone 101 TZ Database String DHCPv4

user-auth 98 User Authentication DHCPv4

DHCP Options
51
DHCP Options
Option Validation Types

Cisco Prime Network No. Option Name Category

Registrar Name

user-class 15 User Class DHCPv6

v-i-vendor-class 124 Vendor Identifying DHCPv4

Vendor Class

v-i-vendor-opts 125 Vendor Identifying DHCPv4

Vendor Options

v4-pcp-server 158 DHCPv4 PCP server DHCPv4

v4-portparams 159 DHCPv4 Port Parameters DHCPv4

v6-pcp-server 86 DHCPv6 PCP Server DHCPv6

vendor-class 16 Vendor Class DHCPv6

vendor-encapsulated-options 43 Vendor Specific DHCPv4

Information

vendor-opts 17 Vendor Specific DHCPv6

Information

vpn-id 68 VPN Identifier DHCPv6

vpn-id 185 VPN Identifier DHCPv4

www-servers 72 WWW Server Servers

x-display-managers 49 X Window System Servers

Display Manager

Option Validation Types

The table below defines the DHCP option validation types. Note that you cannot use some of them to define
custom options.

Table 12: Validation Types

Validation Description—Web UI Equivalent

AT_BLOB List of binary bytes—binary

AT_BOOL Boolean—boolean

AT_CONTAINER6 DHCPv6 Option Container (not usable for custom

options)

AT_DATE Bytes representing a date—date

AT_DNSNAME DNS name—DNS name

DHCP Options
52
DHCP Options
DHCP Options

Validation Description—Web UI Equivalent

AT_INT Unsigned 32-bit integer—unsigned 32-bit

AT_INT8 8-bit integer—unsigned 8-bit

AT_INTI Unsigned 32-bit integer (Intel)—unsigned 32-bit

(Intel)

AT_IPADDR 32-bit IP address—IP address

AT_IP6ADDR 128-bit IPv6 address—IPv6 address

AT_MACADDR Bytes representing a MAC address—MAC address

AT_MESSAGE Unsigned 8-bit message (not usable for custom

options)

AT_NOLEN No length (used for PAD and END only)

AT_NSTRING Sequence of ASCII characters—string

AT_OVERLOAD Overload bytes (not usable for custom options)

AT_RANGEBYTE Range of bytes (not usable for custom options)

AT_RANGESHORT Range of shorts (not usable for custom options)

AT_RDNSNAME Relative DNS name—relative DNS name

AT_SHORT Unsigned 16-bit integer—unsigned 16-bit

AT_SHRTI Unsigned 16-bit integer (Intel)—unsigned 16-bit

(Intel)

AT_SINT Signed 32-bit integer—signed 32-bit

AT_SINT8 8-bit integer—signed 8-bit

AT_SINTI Signed 32-bit integer (Intel)—signed 32-bit (Intel)

AT_SSHORT Signed 16-bit integer—signed 16-bit

AT_SSHRTI Signed 16-bit integer (Intel)—signed 16-bit (Intel)

AT_STIME Signed 32-bit signed integer representing

time—signed time

AT_STRING Unrestricted sequence of ASCII characters—string

AT_TIME Unsigned 32-bit integer representing time—unsigned

time

DHCP Options
53
DHCP Options
DHCP Options

Validation Description—Web UI Equivalent

AT_TYPECNT Type requiring two child definition: size of the type

field, and type of data—counted-type:
For the DHCPv4 dhcp-user-class-id option (77), the
repeating pattern is:

[ len (1 byte) ] [ data, of single type ]

For the DHCPv6 user-class option (15), the repeating

pattern is:

[ len (2 byte) ] [ data, of single type ]

AT_VENDOR_CLASS Vendor-class option (enterprise ID followed by

opaque data; if DHCPv4, enterprise ID is followed
by EID length)—vendor-class

AT_VENDOR_OPTS Vendor-specific options data (enterprise ID followed

by TLVs of vendor-specific data; if DHCPv4,
enterprise ID is followed by EID length)—vendor-opts

AT_ZEROSIZE 32 bits of zero size (no longer used for PAD and END)

Note AT_TIME takes the value entered in seconds, by default. For example, if you enter 60, it is taken as 60 seconds
and if you enter 60s/60m/2h, it is taken as 60 seconds/60 minutes/2 hours and displayed as 60s/60m/2h.

DHCP Options
54