How to disable EXIM port 2525?

Question

Exim

I need to put 2 programs interacting by mail ports
worth
netstat -tulpn | grep :25 and 2525 - listens to Exim
how to safely switch it only to port 25, and will there be glitches in the process, for example, in the work of roundcube?
Or is 2525 an auxiliary port?

Answer 1

2525 - optional. You can disable or disable it by removing it from the daemon_smtp_ports parameter in the Exim configuration