Questions tagged [dhcp]
DHCP stands for Dynamic Host Configuration Protocol and is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol.
2,164 questions
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DHCP Failover port 647 not listening on partner server
I’m having an issue with my Windows Server DHCP failover configuration. I have two domain controllers, both running the DHCP Server role and configured for failover (Load Balance mode). Everything ...
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139 views
VPN clients unable to access some network resources
I have a local network behind a Ubuntu server doing NAT, iptables, OpenVPN, and VirtualBox, all IPV4. I need VPN clients to access machines in local network. Local net is 192.168.1.0/24 and VPN net ...
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2 votes
1 answer
228 views
dnsmasq: map a specific domain to the destination IP address of the incoming lookup query
I have dnsmasq and a Node server running on the same machine. The Node service's listening port is open to all interfaces (0.0.0.0), and whenever dnsmasq receives a query for the domain associated ...
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43 views
Restrict DHCP Requests By Hostname
I'm currently using a MikroTik RB450G as the DHCP server, with a trunk link from the core switch carrying 11 VLANs that all need DHCP services. My requirement is: Only devices with the hostname "...
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137 views
Things to do after DHCP offer and DHCP ack in Ubuntu [closed]
I have sent DHCP Discovery and Request and get response of DHCP Offer and ACK in Python scapy. What do I need to do after getting DHCP offer? I have change my Ethernet adapter IPv4 as per DHCP offer. ...
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119 views
Why are there still DHCP records for NetworkManager in the logs even though the NetworkManager service is disabled in Almalinux 9.6?
I disabled the NetworkManager.service and enabled traditional network-scripts on AlmaLinux 9.6. Why does NetworkManager still perform a DHCP request during system startup? This causes the eth0 network ...
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1 vote
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112 views
How to network-boot Debian clients without modifying the main DHCP server (PXE alternatives)
Summary: In our network, we need to boot Debian 6, 9, or 12 clients over the network, preferably loading the entire OS into RAM. The goal is to be able to serve multiple system versions and custom ...
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34 views
Can I use both Dhcp4 and DhcpDns in a kea-dhcp4 configuration?
I am trying to use ISC Kea as my HA DHCP server, with the DHCP-DDNS functionality. I fail at a very early stage. Consider the minimal configuration file: { "Dhcp4": { "...
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Behavior of DHCP with Two Servers – One with MAC Filtering
I'm trying to get a deeper understanding of how DHCP works in a situation where multiple DHCP servers are present in the same network. In my Scenario there are two DHCP servers on the same subnet. One ...
1 vote
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86 views
Can you give me a pxelinux version of this gpxelinux menu?
I have been using this in 2013 boot of windows 7, I would like to convert this to pxelinux due to its newer, and might also support win 10... default menu.c32 prompt 0 timeout 1 menu hidden label aoe ...
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1 answer
75 views
Ignore tftp PXE server on Cisco IOS Switch
I have a Cisco SG350-10P switch running firmware version 2.5.9.54. It gets its IP address via DHCP from the main router. Elsewhere in my network, there is a tftp server hosting a PXE boot file (...
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SOME static IP clients can access the internet, others can't. Why?
Debian 12, running isc-dhcpd-4.4.3-P1 DHCP Configuration file. NB: I've removed all but two host definitions and these definitions highlight my issue, explained below. option domain-name "home....
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219 views
Kea DHCP server: Creating reservations using circuit-id AND another filter (e.g. MACADDR or client-class)
I am having trouble configuring ISC Kea DHCP server to create reservations using circuit-id AND another filter (e.g. MACADDR and/or client-class). Well, I know I cannot use two client identifier ...
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111 views
ISC DHCP server does not release backup leases in partner down state
I have a DHCP HA setup on two gateway devices. I also have a script that simulates clients requesting IPs from these servers. I want to test out the behavior of these gateways in partner-down state, ...
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88 views
NetworkManager keeps restarting dnsmasq?
I just tried to get internet sharing working with NetworkManager and dnsmasq and checked the logs to find this: Feb 17 02:08:30 archHiLinux1 NetworkManager[455]: <info> [1739776110.6114] dev>...
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2 votes
2 answers
157 views
DHCP when using default VLANs
I have a question about Windows DHCP scopes. Site A is local and has scope 10.0.0.1/24 and hosts the Windows DHCP Server on 10.0.0.5/24. No devices are on the default VLAN. Site B is remote. Devices ...
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0 votes
1 answer
461 views
dhcpcd exited during network booting of Ubuntu
Here is an overview of my setup: I have a tftp server hosting the vmlinuz and the initrd.img file. The one that I'm using is an ubuntu-lowlatency kernel designed for HPC machines (https://unix....
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251 views
How to use MetalLB for exposing Kubernetes services inside a Proxmox VM on a server where only the host has a static IP address?
We have a small server at our institute that I am trying to convert into a master Kubernetes node that will run some ML stuff and provide a couple of web apps to interact with the models. I had a ...
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2 votes
1 answer
760 views
NetworkManager: When DHCP fails, how to either ignore lease expiry, or use a static conf as a *temporary* fallback
We are deploying devices (Linux with NetworkManager) in IPv4 networks that we have no control over. Some of them feature unreliable DHCP services (e.g. dodgy broadband routers) that might disappear ...
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2 answers
363 views
DHCP Entries in ADSI Edit
I have two DHCP servers (2019 Domain) on my network. So I looked into ADSI Edit to see the entries listed there and this is what I found: CN=server01.mydomain.net CN=server01.mydomain.netCNF:ba47eb2c-...
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1 vote
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658 views
DHCP Server -> Client port requirements
I've got two Windows Server 2022 machines that are in DHCP Failover hot-standby configuration. In addition, within the hot-standby configuration there are a number of scopes. My question are: 1- I ...
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1 vote
1 answer
75 views
Proxmox 7 - Randomly removing DHCP data
I run a Proxmox 7 instance (non-enterprise), and randomly, ip a shows no address, and I can't reach the outside network, and the outside network can't access it. If I use dhclient, it fixes it, but ...
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661 views
Ubuntu 22 not getting ip from dhcp on boot
We have a network with ISC running and serious number of VMs running in the same network. While this specific Ubuntu is booting it does not get IP from DHCP. According to DHCP logs, ISC is giving the ...
-1 votes
1 answer
394 views
PXE does not make dhcp request
I was experimenting with DRBL. In order to do it, I've created two virtual machine in VMWare Workstation. The two virtual machines are connected together by a virtual private network, host only, with ...
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124 views
How to access IP and port configuration of the tablet running Linuxmint with "hostapd + DHCP"
My task: Configure and run Access Point (AP) on the tablet (x86) with Linuxmint with access from devices connected to the created AP. Background as additional information (but this is not the topic of ...
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49 views
External IP answering DHCP requests
Testing the DHCP with "DHCP Find Version 1.2" and leaving it open for some time, it shows DHCP offers from an external / public IP. How is this even possible? We use a network within 192.168....
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94 views
Windows Server gets IP address via DHCP for too long
I don't know if I specified the correct title, but the point is that Windows Server tries to get an IP address within 2-3 seconds. But at the moment when the lease renewal occurs, the server has no IP ...
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1 vote
1 answer
374 views
AlmaLinux 8.10 VPS hostname keeps getting overwritten, probably by NetworkManager
On AlmaLinux 8.10 .... I am trying for over 12 hours to change hostname permanently so it does not change back when I reboot. Very frustrating. With most servers it works with hostnamectl set-hostname ...
- 1,262
0 votes
1 answer
135 views
windows server DHCP multiple scope relay trouble
I want to create 14 subnets (10.10.10.0/23, 10.10.20.0/23, 10.10.30.0/23, etc) I have a DHCP server running on a 15. subnet, 10.100.10.0/24 with the address of 10.100.10.100. The problem that arises ...
0 votes
1 answer
349 views
DNS server not being used for resolution on an AWS VPC network
I have a VPC in AWS with multiple public and private subnets in different availability zones. I want to host my own DNS on this network to use single label hostnames. For example, I want to use ...
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0 votes
1 answer
136 views
Dhcp range with fixed Ips
Here I have a DHCP server with some IPs with fixed IPs that are in the range 192.168.1.91-254. And for the leases only the range 192.168.1.11-90. But I want to make the lease range bigger can I use ...
3 votes
2 answers
667 views
DHCP assigned addresses following devices/users and routing
We have three campuses and two data centers. We are considering assigning IP addresses to devices based on the department, so people can move between campuses and those campuses connect to ...
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1 vote
1 answer
342 views
Can a docker container get a hostname from an existing central DHCP server?
Given: We have a service that is currently run on a VM with a MAC address of 4E-3C-FC-EF-C5-45. Our DHCP server assigns it a name of "pixie1". The IP address doesn't matter because ...
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Windows Server 2022 Hyper-V DHCP Lease code 83
I need help with Hyper-v Windows Server 2022. Recently Spinned up a new Cluster on Win 2022 and I am facing Network challenges with the VMs not seeing the Network. But only the ones deployed without ...
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1 vote
1 answer
630 views
Unable to Connect to AMT on HP Z4 Workstation with MeshCommander Due to Unknown IP Address
I'm having trouble using MeshCommander to connect to the AMT in my HP Z4 Workstation because I don't know the IP address, and MeshCommander isn't finding anything. According to the HP Bios Simulator ...
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1 vote
1 answer
831 views
Enable option 66 and option 67 in kea dhcp
How can we enable option 66 and option 67 in kea dhcp. We are using kea dhcp version: 2.1.1 on debian. We could not find much about it, any help would be appreciated. Thank you in Advance :)
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1 vote
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337 views
Freeradius dhcp relay
I have a freeradius v3 running on my raspberry pi together with pihole. I have a external NGFW acting as a DHCP Server. I want the freeradius to "forward" all DHCP requests to the firewall, ...
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120 views
DHCP clients losing current DNS configuration after DHCP server goes offline
We have TWO Domain Controllers, one with DHCP and DNS roles installed(DC1) and the other with just DNS(DC2). For a while the scope options did NOT include a second DNS as an option but it's been about ...
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2 votes
0 answers
1k views
How to retrieve DHCP information when using systemd-networkd?
Our Ubuntu 22 machines have networking configured using netplan and systemd-networkd. Network manager (and therefore nmcli & co.) are not installed. In a bash script, I am looking to extract ...
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1 answer
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how to ingress correctly in kuberenetes with nginx-ingress
I'm new to k8s and I'm having slight trouble setting up a local cluster on virtual machines and have it be accessible from at least my host machine. setup. I've a local cluster consisting of three ...
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2 answers
760 views
How to remotely add reservation to DHCP Server using PowerShell?
Administrators have restricted RDP access to our DHCP server. I need to add an IP address reservation for a MAC address. How do I remotely add an IP address reservation on the DHCP server using ...
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1 answer
508 views
Why is MikroTik router DHCP server delivering ISP's gateway address in addition to router gateway address?
I am doing a very basic setup with a MikroTik router: an ISP modem in bridge (dumb modem) mode, a static public IP, router with DHCP server enabled, LAN. I have followed manufacturer's "Getting ...
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-1 votes
1 answer
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Detect DHCP poisoning with cheap hardware
DHCP snooping is a feature that allow switches to prevent DHCP starvation and DHCP poisoning (MITM attacks on LAN). But these features are not available on cheaper, domestic equipment such as entry-...
0 votes
1 answer
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Windows Server - many event id 4625 authentication failures
In a small network environment, we have one Windows Server with Domain Controller, DHCP and DNS. When every non-domain Windows client connects to the network, a lot of 4625 logon failure events are ...
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2 answers
511 views
How to synchronize time between two devices on a local network using NTPD, with one device serving as both client and server on separate interfaces?
I am using STM32MP1 based two devices which runs on Yocto Linux platform. Among them one has two network interfaces (wlan0, wlan1) where wlan0 is used for connecting with internet servers & wlan1 ...
user1074060
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1 answer
437 views
In the event of a DHCP server outage and a lease time of 7 days, how long will a client keep using its assigned address?
There are a lot of questions about DHCP servers/clients/leases, but I haven't found one specifically addressing this. If I set up a DHCP scope with a lease time of (say) 7 days, and the DHCP server at ...
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0 votes
1 answer
412 views
Unable to manage existing IP address ranges in IPAM after its installation
I have an environment with one Windows server that is running as DC, DNS and DHCP server. In my LAN, I have one network: 192.168.10.0/24. On another server, I've installed Microsoft IPAM server (as a ...
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1k views
Combining DHCP with static IP using systemd
Basically I want to set a static IP with systemd, but I want to get everything else (read "the routes of the network") via DHCP. This is easily done on macos for example which has the option ...
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1 answer
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Ensuring Windows 10 computer joins correct subnet via DHCP
I'm setting up a proxy/firewall and I want it to be the DHCP server for windows clients. The problem is that if I set DHCP to automatic on the windows clients, they will sometimes select the network's ...
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1 vote
2 answers
1k views
DHCP starting before network is ready
I am having a problem with my DHCP server. When it restarts the isc-dhcp-server does not get ready because the network (it uses NetworkManager) is not ready. I put a sleep command in the isc-dhcp-...