portsnap fetch && portsnap update
cd /usr/ports/mail/popa3d/
make install clean

1. Edit your /etc/inetd.conf to use popa3d. The line should look like this:

pop3 stream tcp nowait root /usr/local/libexec/popa3d popa3d

Note: when started via an inetd clone, the logging of connections is left
up to that inetd clone or TCP wrappers.

2. Reload inetd

# /etc/rc.d/inetd reload

Или

echo 'popa3d_enable="YES"' >> /etc/rc.conf

/usr/local/etc/rc.d/popa3d start
netstat -an | grep 110
tcp4 0 0 *.110 *.* LISTEN