Edit/etc/sysctl.conf File added
Net.ipv4.tcp_syncookies = 1
Net.ipv4.tcp_tw_reuse = 1
Net.ipv4.tcp_tw_recycle = 1
Then execute the following command to make the result immediately effective:
Sysctl-p
Description
Net.ipv4.tcp_syncookies = 1 means that Syn Cookies are turned on. When there is a SYN wait queue overflow, cookies are enabled to protect against a small number of SYN attacks, the default is 0, which means close;
Net.ipv4.tcp_tw_reuse = 1 means turn on reuse. Allows time-wait sockets to be re-used for new TCP connections, which defaults to 0, which means shutdown;
Net.ipv4.tcp_tw_recycle = 1 means a fast recycle of time-wait sockets in the TCP connection is turned on, and the default is 0, which means shutdown.
Net.ipv4.tcp_fin_timeout = 30 means that if the socket is closed by the local side, this parameter determines how long it remains in the fin-wait-2 state.
Net.ipv4.tcp_keepalive_time = 1200 indicates the frequency at which TCP sends keepalive messages when KeepAlive is employed. The default is 2 hours, which is changed to 20 minutes.
Net.ipv4.ip_local_port_range = 1024 65000 indicates the range of ports used for an outward connection. Small by default: 32768 to 61000, 1024 to 65000.
Net.ipv4.tcp_max_syn_backlog = 8192 Indicates the length of the SYN queue, the default is 1024, and the queue length is 8192, which can accommodate more network connections waiting to be connected.
Net.ipv4.tcp_max_tw_buckets = 5000 indicates that the system maintains the maximum number of time_wait sockets at the same time, and if this number is exceeded, the time_wait socket is immediately cleared and a warning message is printed. The default is 180000, which changes to 5000. For Apache, Nginx and other servers, the parameters of the last few lines can be a good way to reduce the number of time_wait sockets, but for squid, the effect is not small. This parameter controls the maximum number of time_wait sockets, preventing squid servers from being dragged to death by a large number of time_wait sockets.
Modify Linux kernel parameters reduce time-wait