Tuning the Client

Purpose

Modify some parameter settings in the OS to improve client network performance.

Procedure

1. Open the /etc/sysctl.conf file.

   1	vim /etc/sysctl.conf

2. Press i to enter the insert mode and add the following content to the file:

   net.ipv4.ip_local_port_range = 1024     65535
   net.ipv4.tcp_tw_reuse = 1
   net.core.somaxconn = 65535
   net.core.netdev_max_backlog = 8096
   net.ipv4.tcp_max_syn_backlog = 8192
   net.ipv4.tcp_keepalive_time = 600
   net.ipv4.tcp_fin_timeout = 30
   net.ipv4.tcp_max_tw_buckets = 3000

   Table 1 Network parameters

   Parameter	Description
   net.ipv4.tcp_tw_reuse	TIME-WAIT sockets can be reused for new TCP connections. 0: disabled (default) 1: enabled
   net.ipv4.ip_local_port_range	Port range for external connections
   net.core.somaxconn	Maximum length of a network port listening queue. This is a global parameter and the default value is 128.
   net.core.netdev_max_backlog	Maximum number of packets that can be sent to a queue when the packet receive rate of each network port is faster than the kernel processing rate.
   net.ipv4.tcp_max_syn_backlog	Length of a queue of connections that are waiting for a client confirmation message (SYN). The default queue length is 1024. You can increase the queue length to 262144 to accommodate more waiting network connections.
   net.ipv4.tcp_keepalive_time	Time that a socket remains in the FIN-WAIT-2 state when the socket is to be disabled on the local end
   net.ipv4.tcp_fin_timeout	Enables quick reclamation of the sockets in TIME-WAIT state during TCP connection establishment. The default value 0 indicates that quick reclamation is disabled.
   net.ipv4.tcp_max_tw_buckets	Maximum number of TIME_WAIT sockets. The default value is 180000.

3. Press Esc, type :wq!, and press Enter to save the file and exit.
4. Make the modification take effect immediately.

   1

   sysctl -p