Listening on port 25 to receive mail

["Rocky Hotas" <rockyhotas%post.com@localhost>]

Hi everybody,
I tried to send an e-mail from a host in a LAN to another host in the *same* LAN which runs NetBSD. But the connection was refused because the NetBSD host is not listening on port 25.
How could I make it possible?
First I installed sendmail from pkg. Then, following the instructions at the end of the installation, I forced the symbolic link

/usr/sbin/sendmail (which initially pointed to /usr/sbin/mailwrapper)

to point to /usr/pkg/libexec/sendmail/sendmail.
Next, I put the line

sendmail=YES

in /etc/rc.conf. However, after rebooting, in the output of

netstat -an -f inet |grep LISTEN

there was anything about port 25.
Should I make anything else, or should I correct my configuration?
Thank you,

Rocky