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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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Cannot connect to TCP service from remote host

I have two servers running RHEL 5.8. SRV1 (10.58.192.36) has a service running on port 9002 and I need to connect to this service from SRV2 (10.58.192.42). [root@SRV1 ~]# netstat -anp | grep 9002 tcp 0 0 :::9002 :::* LISTEN 20740/java If I try to…
nvh
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TCP [RST,ACK] ignored

I have a Windows 2008 server and an application that connects over Internet to it. From time to time I see that I receive a TCP [RST, ACK] that is ignored by my application. Using TCPViewer I still can see that connection still up. I did different…
Adrian R
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High number of TCP RST packets

Whilst looking into some transient network issues, I have noticed what seems to be a high number of RST packets received: Tcp: 40091950 active connections openings 44754733 passive connection openings 2840116 failed connection…
Nathan Foley
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Am I under DDOS?

I have a mail server, Debian Linux 2.4.31, which is dropping TCP connections and basically being unavailable. I have iptables running on it and its pretty much very restrictive. When I run "netstat -tanp|wc -l" i get 366 while "cat…
A4A
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Connection Timeout Issues - Solaris 11 SPARC

We're currently running some performance tests using Solaris 11 (SPARC) on some large hardware. The tests, which consist of sending SOAP requests (50kb per request), are running well up until we get into the multiple of thousands of users i.e…
user3474444
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Single TCP-CLOSE_WAIT connection brings down application till restart

Recently found a behaviour where my application had a connection in TCP Close_wait state till the app was restarted (after about 5 hours). But during this period the SUnreclaim space was also increasing constantly and went down on restart. The…
broun
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cannot send emails to other Web servers

I'm trying to limit my server's open ports in CSF. The IPv4 port settings include: # Allow incoming TCP ports TCP_IN = "22,25,53,80,110,143,443,587,3654,53343” # Allow outgoing TCP ports TCP_OUT = "22,53,80,113,443,465,995,3654" # Allow incoming…
developer
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FortiBalancer and IE TCP issues

We are using a Fortibalancer for our web servers (Win2012 with IIS) and we have run into a strange issue. IE users will experience timeouts (~77s) in getting a response from our servers. Packet traces show ZeroWindow probes and ACKs happening at the…
schroeder
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Prevent TCP Connections from Timing out on Restarting Service

On Ubuntu 14.04, an app communicates with clients at intervals of about 1 per sec to 1 per min. However the service have to be restarted regularly and this causes all the connections to drop/timeout. It takes only about 10-15sec for the service to…
Nyxynyx
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Strange data in HTTP request

I have a HTTP server that serve many short time connections from many clients, the server logged that there are some invalid HTTP requests, so I decide to capture the network traffic. This is what I got: ![image][1] Because of HTTP keep-alive, the…
secmask
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TCP RST from telnet/ssh daemons when connecting from openvpn

I have LAN_1 and LAN_2 interconnected with an openvpn tunnel terminated ona pair of SOHO routers running busybox. One of the vpn purpose is to allow clients on both LAN_1 and LAN_2, to administer the two routers themselves, so telnet/ssh connection…
rokafeller
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TCP Python Server

I have a question regarding connection reliability running a tcp server from an ec2 instance. We are currently serving mobile customers around the world from the Oregon region using a c3.4xl ec2 instance. Our product is a live game server written in…
Zach
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apache2 keepalive and opening a tcp connection

An IP packet contains a payload, such as HTTP information, which in turn contains html information. An IP packet is encapsulated into a TCP segment, which detects problems in transmission over networks, requests retransmission of lost data,…
JohnMerlino
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Debugging slow transfer rate from server

I'm trying to explain this as simple but documented as possible. This is not exclusive to this server or my current ISP. I've seen the same exact issue over the years while being with different ISPs and having my servers with different providers…
Francisco Zarabozo
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FreeBSD Established Connections Maxing out at 300

We've previously had issues in our environment where it seemed we were reaching FreeBSDs max connection limit. We took action demonstrated by http://nginx.org/en/docs/freebsd_tuning.html and bumped up our connections limit to 500:…
cheesesticksricepuck
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