Questions tagged [network-protocols]
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106 questions
1 vote
0 answers
84 views
Outlook for Windows not connecting one GoDaddy account, but same config works perfectly in Thunderbird [closed]
Im using Microsoft Outlook Version 1.2025.829.200 (the new WebView2-based Outlook for Windows) on Windows 11. I have a GoDaddy IMAP email account. When adding an account, the following error occurs: ...
- 111
0 votes
0 answers
44 views
Netperf return MIGRATED TCP STREAM TEST from (null) (0.0.0.0)
I am using Netperf tool to benchmark throughput and latency. My Netperf pod is running in AWS EKS (Kubernetes), behind an HAProxy load balancer. The flow is as below: client ---> HA proxy --> ...
- 101
0 votes
0 answers
626 views
Can Nginx pass through PROXY protocol destination address/port?
We have Nginx running as a TCP proxy configured to receive PROXY protocol data from a downstream load balancer and send PROXY protocol data to an upstream server: stream { server { listen ...
- 252
0 votes
1 answer
752 views
Why do udp and udp6 have different port behaviors?
I have two Linux servers. I run the same Java application on both of them. One of them runs as udp and the other as udp6. When I send a request to the udp application, it returns to me over a ...
-1 votes
1 answer
171 views
Why Google SMTP MTA's are not sending STARTTLS command
I'm a software engineer that wrote my own SMTP delivery agent. I recently added the STARTTLS support to my software and I was doing some testing, when I noticed that Google's SMTP transfer agents are ...
- 681
-2 votes
1 answer
2k views
How browsers deal with ports? [closed]
Suppose I've a website created which is hosted, and running on port 5000. Now you are on a web browser (let's say chrome) visits the webpage. so does chrome sends a request from your PC to my server ...
- 97
0 votes
0 answers
82 views
How do you prove RFC 791 - Internet Protocol
We are being asked to prove we are using RFC 791 (Internet Protocol) within our network. How does one prove such a thing via documentation if there is no such document from the vendor stating as much....
- 145
0 votes
1 answer
360 views
Spanning Tree Protocol: How are ports selected to be designated or non-designated?
I have read a lot about STP now. Perhaps not enough yet, but it starts to get difficult to get details. I have understood the mechanism how all bridges select their root port. After having exchanged ...
- 103
0 votes
1 answer
217 views
can http clients configure if they want persistent or non-persistent connections with the http server?
I want to understand, if depending on how client configures the http connection, the server can behave in non-persistent manner or persistent manner, so in effect some clients can connect in ...
- 103
0 votes
2 answers
964 views
Does http protocol standard support long polling?
I recently read about long-polling concept which can be used with http. I want to understand, if any http protocol standard itself supports long-polling concept, so that depending on how client ...
- 103
0 votes
1 answer
63 views
Reliable transfer protocol designed for a known static bottleneck size and high packet loss?
AFAIK, most reliable transfer protocols like TCP tends to use some method (like packet loss) to detect the size of the bottleneck. In my use case, however, the bottleneck bandwidth is a known value of ...
0 votes
1 answer
443 views
IPv6 Protocol failure
I am having a weird issue with IPv6 in my Windows Server 2019 Domain Controller. I was trying to configure IPv6 for the domain, I've typed some commands as below, when I restarted the server it doesn'...
- 11
0 votes
1 answer
2k views
How can I isolate a single TCP connection on Wireshark?
I just started using Wireshark for network troubleshooting purposes and I am a little confused about one thing. I requested a webpage and for the next 10s I monitored the data. I then used the filter ...
user603679
-2 votes
3 answers
3k views
DNS and OSI Layer Working
I would like to clarify a doubt that's haunting me after learning DNS. I'll briefly write it as a question. "A user was watching a video in youtube and suddenly the DNS server which was used by ...
- 11
5 votes
3 answers
3k views
Is the Matrix protocol Fediverse?
The title says it all. Reading about the Fediverse, the Matrix protocol seems to fit its characteristics, however I found no reference of that anywhere.
- 81
0 votes
0 answers
133 views
Rekeying denies protocols/NAT issue or config?
I'm using strongswan to connect to a MAC server using IKEv2/IPsec configuration. The server uses the proposed algorithms to establish the SA and everything works great. Upon rekeying however, the ...
0 votes
1 answer
439 views
Do ports change for every request? Are Ip ports are different from system ports?
A typical ip address has >65k ports then again a system that runs localhost offline has port which sometimes face conflicts. Am very under-read in this area please give some light. Pardon my English. ...
- 1
0 votes
1 answer
3k views
UDP is received, but TCP is not
I have two types of software connected to the internet - both HAVE to be continuously connected. One connects via UDP protocol and I have no dropouts. The other maintains its connection through a TCP ...
- 1
0 votes
1 answer
740 views
DNS server - respond to client with "go resolve from that DNS server"
I'm trying to figure out how to build a DNS response that refers the requesting client to try resolve from a different DNS server. For example, Client PC makes a request to resolve A record "google....
0 votes
1 answer
183 views
Is AS2 versions backwards compatible?
Is AS2 version 1.2 compatible with version 1.1? If I'm sending messages from system using version 1.2 to a system that only supports version 1.1 will the message get delivered ok? Messages would be ...
- 1
2 votes
1 answer
644 views
What exactly happens when a TCP segment is sent to a broadcast address?
Does the segment get delivered -- and the recipients are supposed to drop it? Does the segment get dropped at the (layer 3) switch/router? Or something completely different? Explanations or "RTFM!" ...
- 123
1 vote
1 answer
38 views
Why does LAN stops working if switch is connected to two upfeeds?is [closed]
If I connect my switch to two upstream feeds from my ISP, my internal LAN stops functioning (see illustration below). What is it in the TCP/IP protocol that is disrupted to cause the above? ...
- 1,069
0 votes
2 answers
2k views
Prevent Unjoined-to-domain computers from connecting to my network
How to prevent any computer that is not joined to the domain from requesting any service from my network? Considering that the computer is on another network.
- 11
-1 votes
1 answer
741 views
Security issues with SMTP
I am looking at SMTP and POP3 and am trying to find the security issues with both protocols, I have found that SMTP can be easily impersonated on port 25. However I am struggling to find security ...
1 vote
0 answers
312 views
How does VXLAN prevent duplicate MAC addresses?
It seems to me that VXLAN network identifier(VNI) works silimar to a prefix keeping identical MAC addresses on different VXLAN segments separate, so that they can coexist without duplication issues. ...
- 133
0 votes
1 answer
237 views
What application is connecting to a remote site?
I can see with Wireshark that every 5 minutes I have a connection from my computer to ip 165.254.162.243 on udp/8253. This has been going for months. I cannot identify what application or process is ...
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5 votes
1 answer
4k views
What's URD in iptables?
I've been playing around with various iptables configurations lately, and I noticed that adding a rule which involves --dport 465 (usually reserved for smtps) results in the human-readable dpt:urd ...
- 201
-1 votes
1 answer
5k views
raw sockets, iptables and the fact that
iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT DROP So, I just found out that these cute rules don't do s**t when it comes to raw sockets. I know that grabbing a raw socket ...
- 11
0 votes
0 answers
152 views
Installing Unsigned Network Protocol Driver Windows 2012R2
I'm trying to install an unsigned Network protocol driver on a 2012 R2 Windows server installation however the installation just fails the same way unsigned device driver fails. I've already unlock ...
- 101
0 votes
1 answer
51 views
Simultaneous http requests planning
A development Meteor app runs in a docker container on aws cloud, it accepts user input and makes HTTP requests to 3rd party websites, parses the data and sends back to the user. Apology; my limited ...
- 161
1 vote
1 answer
321 views
Huawei Secospace USG 2000 on a non Default Port
I would like to know which is the default port of IPSec. I have tried to connect on all default ports, but I was unsuccessful. Also, I have applied NMap to them, but have no response.
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1 vote
1 answer
4k views
How to capture network packets that use SS7 protocol using Wireshark?
Since SS7 protocol stack is used in GSM mobile telephony network, we can't get the packets of SS7 protocols using Wireshark in Windows Computer and browsing in a web browser like Google chrome. So ...
- 23
-1 votes
1 answer
86 views
Does anything changes for a client in the API communication after the command STARTTLS is sent and a response received
I'm trying to understand how the command STARTTLS in IMAP works exactly and what becomes different when it's sent. After I've sent the command "STARTTLS" before login process and received the response ...
- 113
0 votes
1 answer
449 views
can tcpdump detect higher level protocols like wireshark?
Wireshark will guess what higher level protocols are being used in a packet, but how can I get tcpdump to do likewise (or any other linux command line tool)? For example, the following screenshot ...
- 431
0 votes
1 answer
101 views
Enforce a client hardware address via DHCPv4
Is there a DHCPv4 option that allows a client to tell the server never or at least for some time to deny any other client hardware address than its own? I'm looking for a way to deny any other host ...
- 137
2 votes
1 answer
3k views
What's the legit use of a deauthentication packet?
Most people that have tampered with external wireless networks in a malicious fashion for the sake of education (hopefully your own personal testing network) have probably heard of a deauthentication ...
0 votes
1 answer
822 views
Nic teaming server 2012 r2
I've been asked to build a server and team the nics, my understanding is the nics should each be dhcp enabled and the team should be configured with a static ip. Would this be correct and also what ...
- 353
1 vote
0 answers
76 views
SNMP/PJL - used area printed on a page
How can find the effective area printed on a page direct from printer device? I can't access the file stream to do direct on it.
0 votes
1 answer
6k views
How SMTP (receiving emails) works?
I have a very hard time to understand how SMTP works. I've read already: Message Submission for Mail Internet Mail Architecture Internet Message Format Simple Mail Transfer Protocol I know the SMTP ...
- 329
2 votes
1 answer
916 views
Why is the DHCP lease start time greater than the end time
On our DHCP server I see this quite a bit on some of our leases and I am not sure why its being reported like this. lease <IP Address> { starts 5 2015/08/21 13:22:20; ends 5 2015/08/21 13:22:...
- 649
1 vote
1 answer
179 views
MAC Layer Retransmissions during the same TXOP
Back in the day I was messing around with MadWifi and, if I remember properly, after a packet was transmitted if the sender did not receive an ACK in SIFS time after the completion of the transmission,...
- 133
32 votes
2 answers
7k views
Under what circumstances is TCP-over-TCP performing significantly worse than TCP alone (2014)?
Many admins keep perpetuating - on ServerFault and elsewhere - how bad of an idea TCP-over-TCP is, e.g. in VPNs. That even the slightest packet loss will make one suffer from at least severe ...
- 3,622
0 votes
1 answer
99 views
Worldwide IP Latency [closed]
I want to create a simulation of the protocol MIPv6 (http://www.ietf.org/rfc/rfc3775.txt), for this reason I need information about latency, jitter and round-trip time. My first guess is install ...
- 11
-2 votes
1 answer
917 views
Configure Protocols using iptables log file with ndpi [closed]
I am using iptables with ndpi to filter my network and add two rules to my iptables rules they are iptables -I INPUT -m ndpi --http -j LOG iptables -I INPUT -m ndpi --google -j LOG In my log file I ...
- 111
2 votes
2 answers
2k views
What is the KRYPTOLAN protocol?
I've searched for a while and can't seem to find any information on what KRYPTOLAN is. For the transport layer, IP protocol number 0x41 is assigned. In addition, ports 398/udp and 398/tcp are also ...
- 271
0 votes
1 answer
165 views
Token Ring Number of nodes in MAU [closed]
why the token ring has limitation of 260 nodes per MAU using STP cables? How the number of nodes per MAU is calculated? I know we can use more than 260, but why IEEE-802.5 is Standardized it to 260 ...
- 1
6 votes
1 answer
461 views
Tools for detecting network traffic filtering [closed]
In Iran we have an ongoing problem with the govt. blocking and manipulating various network protocols. I'm looking for a tool, framework or platform to help us analyze and report on any of these ...
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1 vote
0 answers
63 views
Routing table taking long time to update for adhoc networks and OLSR
I am using OLSR to implement adhoc network and analyse the throughput.I have olsr working on 3 interconnected computers on adhoc network. I am using jperf to simulate and visualise the data ...
- 111
0 votes
1 answer
977 views
ow to get protocol signatures?
Does anyone know how can we get signatures for various protocols e.g. BGP, DHCP, VxLAN etc? By signatures, I actually mean the pattern (e.g. something like 0x234557888) used for pattern-matching in a ...
- 101
2 votes
3 answers
1k views
Can i set 443 as default web port which means it can only be accessed via https and no port 80
As title says, I want to set my apache to listen on 443, and will configure SSL. So, My Question is :- 1). Does that mean, i will not have port 80 or any other port which is no ssl ? 2). My site ...
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