Friday, June 30, 2017

Reduce TIME_WAIT socket connections

We will reduce the Time_wait by tweaking the Sysctl to time out at a certain time and reuse that socket.

List the no of time_waits and Established Connections

>>netstat -nat | awk '{print $6}' | sort | uniq -c | sort -n

cat /proc/sys/net/ipv4/tcp_fin_timeout
cat /proc/sys/net/ipv4/tcp_tw_recycle
cat /proc/sys/net/ipv4/tcp_tw_reuse

If you have default settings, you’ll probably see values of 60, 0 and 0. Let’s change those values to 60, 1, 1.

Now, edit the /etc/sysctl.conf with your favorite editor and add these lines to the end of it (or edit the values you have in yours if they exist already):

# Decrease TIME_WAIT seconds
net.ipv4.tcp_fin_timeout = 30

# Recycle and Reuse TIME_WAIT sockets faster
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1

Sysctl -p

netstat -nat | awk '{print $6}' | sort | uniq -c | sort -n

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