How do I configure my mail service to run on a different port and avoid a conflict with another active port?
Linode
Linode Staff
I'm looking to run my mail service on a different port than the default setting. However, I'm not sure which new port number to use. How can I avoid a conflict with another active port?
1 Reply
jchism
Linode Staff
You can start by viewing which ports are currently open and listening on your server. Some commands that you can use to verify this are listed below:
netstat -plantu
ss -plant
nmap -Pn localhost
Once this is verified, you can change the configuration file of your mail service to use a port number that's not listed in the results. For example, I use port number 32 for my mail service. Once you make the changes, please ensure that you restart your mail service.
You can also view the "/etc/services" file to see a listing of the default ports that most services listen on.
less /etc/services | more