Tuning of Linux kernel parameters (careful use in production)

Solutions to the emergence of a large number of TIME_WAIT in Linux

In practical work, it is best to let the operation and maintenance staff adjust it.

View command: netstat-ae | grep "TIME_WAIT" | wc-l

Solve the problem by adjusting the kernel parameters: vi / etc/sysctl.conf, add the following

Net.ipv4.tcp_tw_reuse = 1

Enable reuse, allowing TIME-WAIT sockets to be reused for new TCP connections

Net.ipv4.tcp_tw_recycle = 1

Enable fast recovery of TIME-WAIT sockets in TCP connection

Net.ipv4.tcp_fin_timeout = 30

Modify the system default TIMEOUT time

Net.ipv4.tcp_keepalive_probes = 5

Reduce the number of detections before timeout

Net.ipv4.tcp_keepalive_intvl = 20

Detect the frequency of messages sent

Net.ipv4.ip_local_port_range = 1024 65000

Represents the range of ports used for outbound connections

Net.ipv4.tcp_max_syn_backlog = 8192

Indicates the length of the SYN queue. The default is 1024. When it is enlarged, it can accommodate more network connections waiting to be connected.

Net.ipv4.tcp_syncookies = 1

Enable SYN Cookies. When there is a SYN waiting queue overflow, enable cookies to handle it to prevent a small amount of SYN***.

Then execute / sbin/sysctl-p to make the parameter take effect