SELinux permits specified program to use specified ports. We must tell SELinux to permit programs to use non-standard ports if we intend to do something abnormal. For example, if we wanted to run Apache on port 81, we’d have to tell SELinux to permit that. Otherwise we’d get errors. When we manipulate SELinux rules, the process can take some time so don’t stress.
Permit Apache to listen on port 81:
semanage port -a -t http_port_t -p tcp 81
You can confirm the above using the following command:
semanage port -l | grep http_port_t
Here is some sample output:
http_port_t tcp 81, 80, 443, 488, 8008, 8009, 8443
So you can see from the above output that Apache is able to listen on several ports. That doesn’t mean Apache ‘will’ listen on those ports but simply that SELinux will permit it.
