Monday, February 5, 2007

Change the TCP/IP tuning parameters in Linux

All TCP/IP tuning parameters are located under the /proc/sys/net/ directory. For example, here is a list of the most important tuning parameters, along with a short description of their meaning:
  1. /proc/sys/net/core/rmem_max - Maximum TCP Receive Window.
  2. /proc/sys/net/core/wmem_max - Maximum TCP Send Window.
  3. /proc/sys/net/ipv4/tcp_timestamps - Timestamp ( RFC 1323) add 12 bytes to the TCP headers.
  4. /proc/sys/net/ipv4/tcp_sack - TCP selective acknowledgments.
  5. /proc/sys/net/ipv4/tcp_window_scaling - support for large TCP Windows (RFC 1323). Needs to be set to 1 if the Max TCP Window is over 65535.
  6. mem_default = Default Receive Window.
  7. rmem_max = Maximum Receive Window.
  8. wmem_default = Default Send Window.
  9. wmem_max = Maximum Send Window.

Everything under /proc is volatile, so any changes made are lost after a reboot.

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