If you are seeing a large number of connections persisting in a CLOSE_WAIT state, it is probably an issue with the application itself.
Restarting it will clear the connections temporarily, but to find the real cause of the issue you would have to do the investigation.
If restarting of application is undesirable, you can manually kill all connections that are in the CLOSE_WAIT state.
Kill CLOSE_WAIT connections
Kill CLOSE_WAIT connections by IP
Kill TCP connections in CLOSE_WAIT state, established with the foreign IP address 192.168.0.100:
$ netstat -anp |\
grep 192.168.0.100 |\
grep CLOSE_WAIT |\
awk \'{print $7}\' |\
cut -d \/ -f1 |\
grep -oE \"[[:digit:]]{1,}\" |\
xargs kill
The same command in one line :
$ netstat -anp | grep 192.168.0.100 | grep CLOSE_WAIT | awk \'{print $7}\' | cut -d \/ -f1 | grep -oE \"[[:digit:]]{1,}\" | xargs kill
Kill CLOSE_WAIT connections by Port
Kill TCP connections in CLOSE_WAIT state on port 80:
$ netstat -anp |\
grep \':80 \' |\
grep CLOSE_WAIT |\
awk \'{print $7}\' |\
cut -d \/ -f1 |\
grep -oE \"[[:digit:]]{1,}\" |\
xargs kill
The same command in one line:
$ netstat -anp | grep \':80 \' | grep CLOSE_WAIT | awk \'{print $7}\' | cut -d \/ -f1 | grep -oE \"[[:digit:]]{1,}\" | xargs kill
Kill CLOSE_WAIT connections by IP & Port
Kill TCP connections in CLOSE_WAIT, state established with foreign IP address 192.168.0.100 on port 80:
$ netstat -anp |\
grep 192.168.0.100 |\
grep \':80 \' |\
grep CLOSE_WAIT |\
awk \'{print $7}\' |\
cut -d \/ -f1 |\
grep -oE \"[[:digit:]]{1,}\" |\
xargs kill
The same command in one line:
$ netstat -anp | grep 192.168.0.100 | grep \':80 \' | grep CLOSE_WAIT | awk \'{print $7}\' | cut -d \/ -f1 | grep -oE \"[[:digit:]]{1,}\" | xargs kill
Explanation
$ netstat -anp |\ # print network connections grep 192.168.0.100 |\ # established with IP 192.168.0.100 grep \':80 \' |\ # established on port 80 grep CLOSE_WAIT |\ # connections in CLOSE_WAIT state awk \'{print $7}\' |\ # print the 7th column cut -d \/ -f1 |\ # extract PIDs grep -oE \"[[:digit:]]{1,}\" |\ # extract PIDs xargs kill # kill PIDs