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Questions tagged [tcp]

TCP stands for Transmission Control Protocol and is one of the core protocols of the Internet Protocol Suite. TCP complements the Internet Protocol (IP), and therefore the entire suite is commonly referred to as TCP/IP.

TCP is just one communications protocol on the web. Others include:

  • User Datagram Protocol (UDP)
  • Internet Control Message Protocol (ICMP)
  • Hypertext Transfer Protocol (HTTP)
  • Post Office Protocol (POP3)
  • File Transfer Protocol (FTP)
  • Internet Message Access Protocol (IMAP)

TCP on Wikipedia

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Setting Up WAN + LAN Network with pfSense in VirtualBox - Troubleshooting TCP Connection Issue

Hello, I am currently in the process of configuring a WAN + LAN network within VirtualBox using pfSense (VM) as the router in my LAN. The primary objective is to establish communication between a TCP client program on the host machine (WAN) and a…
lcocozza
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First attempt at connecting to any TCP service fails

Symptom: The first attempt at connecting to a TCP service (https, ftp, or ssh) fails. The second attempt succeeds Subsequent connections will work until there is a 15 minute period of inactivity, in which case the next connection will fail again.…
Randall Embry
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All tcp ports are not reachable on localhost (MacOS 13.4)

A friend of mine asked for help, basically any app listening on some local tcp port on localhost can't be reached. For example a node.js server running on port 8080 or 3000. Executing the command sudo lsof -i -P | grep LISTEN | grep 8081 gives: node…
revy
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Proxy TCP connection to different hosts depending on the origin host

I have a home server exposed with NoIP, with a wildcard domain. I have some services that run on some TCP ports (mainly game servers), and I am trying to sort of "assign" each of them a subdomain. To do this, I have a virtual network interface with…
Ciro García
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OpenVPN TCP connection to firewall failing: unknown error

I want to premise that I am not an expert in connectivity, firewalls, routers, and related topics. For the past two days, I have encountered an error when attempting to connect to my office VPN through the OpenVPN software. The error message I…
nanto
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Listening on all interfaces, multiple servers

I have a server listening on all interfaces for a port (using go net.Listen("tcp", ":{port}")). I also have backup server with the same code, to start if first server fails. Both machines using the same router which has an external IP address.…
Lovish Puri
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How to investigate not received TCP packets sent from VPN on the same LAN?

I'm setting up a VLAN on the cloud where many servers will connect to a remote host via VPN. The setup is as follows: Their Host d.d.d.72 | | | Their VPN Public IP…
Younes
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The TCP receiver only ack the minimum bytes of MSS one by one

The client and server nodes are CentOS7.9/X86_64. If the HTTP POST requests were sent directly to the server, there are about 0.2% of cases that may timeout. If the HTTP POST requests were sent through an NGINX proxy on the client node, there are…
exudong
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IP Based Rate Limiting for a TCP passthrough vip

Trying to set this up for one of the applications. We use Nginx under the hood. Is it possible to set up an IP-based rate limiting for a TCP passthrough VIP? I understand that it is possible to set this up for a regular HTTPS vip, where the…
Jerrin
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Proxmox host cannot reach guest: TCP client retransmitting instead of sending ACK after SYN/ACK

Setup: server (HTTP server on 80) on 192.168.1.20, clients on 192.168.1.17, 192.168.1.18 Client 192.168.1.17 can connect to the server fine (Wireshark capture on the client side attached) 1 0.000000 192.168.1.17 192.168.1.20 TCP 78 62275…
Zixian Cai
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php sqlsrv error TCP Provider: Error code 0x271D

when i run php script from browser sqlsrv mssql connection working. but when i execute php script via ssh command "/opt/alt/php-fpm70/usr/bin/php path/to/script.php" sqlsrv_connect give this error: Array ( [0] => Array ( [0] => HYT00 …
Gökhan G.
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Improve connection speed for South America users to server in Europe

I'm running an MMORPG Game with central server based in Europe-Warsaw hosted on OVH. My player base is located both in Europe (mostly Poland) and South America (mostly Brazil). Due to server localization Europe players have very good Ping response…
erexo
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What is the name of the string that a service returns when you establish a tcp connection via telnet?

If you telnet to an ssh server, it will establish a connection and return a string, something like SSH-2.0-OpenSSH.... etc. Something similar happens if you connect to a mysql server. What exactly is the name of the string that the service returns?…
cat pants
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Tuning Amazon Linux for TCP Handshake, receiving 200-300KB response, and then closing connection

I have an application which regularly creates a new TCP connection, makes a request, and then gets a just under ~300KB response before closing down the connection. Assuming that I can't redesign this workload, and that the latency between my side…
Cory Kendall
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Reusing client certificate for TLS proxy with nginx?

I have a TCP application that uses mutual TLS to authenticate connecting clients. Because of increased traffic I'd like to clusterize the application and load-balance the nodes with nginx. I already have that working with nginx's stream module,…
Florian Braun
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