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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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TCP acks are paused, then resumed, then paused again. Why?

I would like some help finding the reason for the reduced data transfer rate in my application. I have 12 embedded systems and a Linux server. The embedded systems send data to the server over TCP on an Ethernet link through a switch. The following…
martinhans
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Always keep socat alive

I have a socat running nicely, executing my command when a connection comes in with the arguments provided. However, the issue I am having is that the socket is at EOF and the next time a connection comes in, the process takes 3 seconds to spin back…
Robbie Trencheny
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TCP under OpenVPN is very slow (tsg attached)

I have a very weird problem with OpenVPN. Most VPNs work fine, except this one. Here I get very low performance from TCP connections, but the CPU load is low (so, not a CPU issue). OpenVPN is configured with UDP, AES-256-CBC cipher, SHA256 auth and…
Pentium100
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How to achieve multiple NFS/TCP connections to the same server?

I'm trying to maximize the NFS/TCP bandwidth between a Linux client and a single NFS server over a 10Gbps link. Although each NFS mount has its own device (major/minor), everything comes down to a single TCP connection and this is a…
Benoît
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tcpdump capturing tcp resets by host

I am trying to figure out where my tcp resets on my webserver happen. I have the following capture: tcpdump -fnni bond0:-nnvvS -w dump.pcap 'tcp[tcpflags] & (tcp-rst) !=0' When I look at the pcap in wireshark shows me resets: Flags: 0x004…
rahrahruby
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TCP/IP routing: accessing a LAN device with wrong static IP configuration

I forgot to change the static IP of a network device before moving it from my datacenter network to my home LAN. Since it isn't configured properly for my LAN network, I'm not sure how to access it. Constraints: It's a NAS (a LaCie Network Space…
Michael McDonald
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tcpdump: snaplen set to 0 but still get "Packet size limited during capture"?

Due to this problem, I'm going to sniff some packets on the MySQL server backend to see what happens: # tcpdump -vv -s0 -c 100 -i bond0 tcp port 3306 and host 192.168.3.87 -w /home/quanta/3.87_aborted.pcap As you can see, I set snaplen to 0, but…
quanta
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Clarification about Linux TCP window size and delays

I have delays when sending data through a TCP channel I am not able to understand. The link is a 1Gb link with a end to end latency of roughly 40ms. In my current setup, latency (the time from one message to go from the sender user space to the…
jlafaye
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Block all incoming DNS requests EXCEPT from IPs x,y,

I want to block all incoming requests on my two DNS servers APART FROM certain IP addresses e.g. IP of 1.2.3.4 will be allowed to make requests but NOBODY else will. How do you do this with iptables? Many thanks.
ale
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Increasing the number of outbound TCP connections

I am developing a small test client for websockets. I am using Ubuntu 11.04 . I have read https://stackoverflow.com/questions/410616/increasing-the-maximum-number-of-tcp-ip-connections-in-linux and I have done the following sudo sysctl -w …
Harihara Vinayakaram
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Forwarding linux terminal from serial port to TCP with socat

I'm working on embedded ARM platform, Slackware. I'm using G24 Java modem which is configured to forward data between ports /dev/ttyS1 and /dev/ttyACM0, so anything that goes onto any of these ports is then visible on the other. I want to set…
Wookie88
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Convey multicast (to another LAN) through WAN disabling multicast

My Server and Client softwares run both on Linux. The Server broadcasts multicast, the Client listens multicast. My Client has to migrate to another site, and unfortunately multicast is not allowed between the two sites :-( How to convey multicast…
oHo
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TIME_WAIT connections not being cleaned up after timeout period expires

I am stress testing one of my servers by hitting it with a constant stream of new network connections, the tcp_fin_timeout is set to 60, so if I send a constant stream of something like 100 requests per second, I would expect to see a rolling…
Mark D
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Server not sending a SYN/ACK packet in response to a SYN packet

Using iptraf, tcpdump and wireshark I can see a SYN packet coming in but only the ACK FLAG is set in reply packet. I'm running Debian 5 with kernel 2.6.36 I've turned off window_scaling and tcp_timestamps, tcp_tw_recycle and tcp_tw_reuse: cat…
jeff
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What is theoretical maximum of TCP traffic over GigaEthernet?

What is theoretical maximum of TCP traffic over GigaEthernet ?
d_pilot
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