Troubleshooting With Netstat
Published on April 13, 2020•Updated on November 21, 2023
netstat (Network Statistics) is useful to query the state of your network connections. It is available for Linux, Windows and MacOS.
Verify your application is listening on the correct port
Run netstat
from the console of your server. Useful command switches are:
-u : Show UDP sockets
-p : Show the PID and name of the program to which each socket belongs.
-l : Show only listening sockets.
-n : Show numeric addresses.
-t : Show TCP sockets
Example:
$ netstat -uplnt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1491/sshd
tcp6 0 0 :::22 :::* LISTEN 1491/sshd
udp 0 0 127.0.0.1:323 0.0.0.0:* 655/chronyd
udp 0 0 0.0.0.0:68 0.0.0.0:* 1312/dhclient
udp6 0 0 ::1:323 :::* 655/chronyd
Review this information to verify your application is listening on the correct local address and socket. Please provide this information to support if you submit a ticket for further debugging.