Port property specifies which local port is
used for accepting new connections. It's default value
110 is well known and 'registered' for usage of
POP3 protocol applications, but in specific cases you might
want to change it to something else. If you do so, please
notify users that will use your server for new port
number.
When you choose this value, please be sure that selected
port is not taken by some other application. If you're
not sure if it's available or not, easiest way to find
out is to execute 'netstat -a' from command prompt
and check if there's 'pop3' or '110'
value listed in 'Local Address' column. In default
installations of all Windows operating systems, POP server
will not be installed so you don't have to worry about
this.
You cannot change value of this property when your
server is running. If you want to change it, first Stop the
server, change the port, and then Start it
again. If there are any users connected at that time, they
will be disconnected.