Can pf block illegal relay access attempts?

[dave]

Hello,
    I'm in an identical situation, my postfix system is getting heavy
traffic from spammers a majority of which are from the asia area. I've got
the beginnings of a concept but don't know how best to implement it. Use a
spammers table and point that to a file that contains one IP address
perline. Then somehow trigger a script that takes an offending ip out of the
maillog or also in my case the ssh log, and drops it in that file. When that
is done pfctl reloads and blocks it.
    Any help or improvements appreciated.
Dave.