Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Performance Tuning Guide

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## TCP/IP Settings

### To tune the TCP/IP settings

1. Add the following entry to `/etc/rc.local`

       echo 30 > /proc/sys/net/ipv4/tcp_fin_timeout
       echo 60000 > /proc/sys/net/ipv4/tcp_keepalive_time
       echo 15000 > /proc/sys/net/ipv4/tcp_keepalive_intvl
       echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

2. Add the following to `/etc/sysctl.conf`

       # Disables packet forwarding
       net.ipv4.ip_forward = 0
       # Enables source route verification
       net.ipv4.conf.default.rp_filter = 1
       # Disables the magic-sysrq key
       kernel.sysrq = 0
       net.ipv4.ip_local_port_range = 1204 65000
       net.core.rmem_max = 262140
       net.core.rmem_default = 262140
       net.ipv4.tcp_rmem = 4096 131072 262140
       net.ipv4.tcp_wmem = 4096 131072 262140
       net.ipv4.tcp_sack = 0
       net.ipv4.tcp_timestamps = 0
       net.ipv4.tcp_window_scaling = 0
       net.ipv4.tcp_keepalive_time = 60
       net.ipv4.tcp_keepalive_intvl = 15
       net.ipv4.tcp_fin_timeout = 30

3. Add the following as the last entry in `/etc/rc.local`

       sysctl -p /etc/sysctl.conf

4. Reboot the system.

5. Use this command to increase the size of the transmit buffer:

       tcp_recv_hiwat ndd /dev/tcp 8129 32768

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- Next: Chapter 6 Tuning for High-Availability

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