| Securing and Optimizing Linux: RedHat Edition -A Hands on Guide | ||
|---|---|---|
| Prev | Chapter 6. Linux General Optimization | Next | 
This hack just make the time default values for TCP/IP connection lower so that more connections can be handled by time on your TCP/IP protocol. The following will decrease the amount of time your Linux box will try take to finish closing a connection and the amount of time before it will kill a stale connection. This will also turn off some IP extensions that aren't needed. The default setup for the TCP/IP parameters we'll change under Red Hat Linux are:
For the tcp_fin_timeout 180
For the tcp_keepalive_time 7200
For the tcp_window_scaling 1
For the tcp_sack 1
For the tcp_timestamps 1
To adjust the new TCP/IP values, type the following commands on your terminal:

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             [root@deep] /#echo 30 >/proc/sys/net/ipv4/tcp_fin_timeout 
             [root@deep] /#echo 1800 >/proc/sys/net/ipv4/tcp_keepalive_time 
             [root@deep] /#echo 0  >/proc/sys/net/ipv4/tcp_window_scaling 
             [root@deep] /#echo 0  >/proc/sys/net/ipv4/tcp_sack 
             [root@deep] /#echo 0  >/proc/sys/net/ipv4/tcp_timestamps
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             # Decrease the time default value for tcp_fin_timeout connection
             net.ipv4.tcp_fin_timeout = 30
             # Decrease the time default value for tcp_keepalive_time connection
             net.ipv4.tcp_keepalive_time = 1800
             # Turn off the tcp_window_scaling
             net.ipv4.tcp_window_scaling = 0
             # Turn off the tcp_sack
             net.ipv4.tcp_sack = 0
             # Turn off the tcp_timestamps
             net.ipv4.tcp_timestamps = 0
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             [root@deep] /# /etc/rc.d/init.d/network restart
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Setting network parameters [ OK ] Bringing up interface lo [ OK ] Bringing up interface eth0 [ OK ] Bringing up interface eth1 [ OK ]