[Mimedefang] Re: rejecting on helo,drive-by-relay,forged_sender,

[Jeremy Mates]

* Chris Myers <chris at by-design.net>
> The wonderful thing about the SpamAssassin scoring system is that none
> of us had mailers that refused all e-mail from the Internet when a
> certain DNSBL went offline by listing the entire Internet as a spam
> source. Sites that used the DNSBL's directly in sendmail as an on/off
> switch lost all their mail for a day or two!

Not with a self-check to see if the RBL is blacklisting everything,
which should include the server itself. Be sure to have a local caching
nameserver handy, which I recommend anyways for a number of reasons.
(For extra fun, make the localhost caching nameserver authoritative for
your domains.)

if (relay_is_blacklisted($SendmailMacros{'if_addr'}, 'sbl.spamhaus.org.')) {
  md_syslog 'crit', "$QueueID: myself listed in sbl.spamhaus.org";
} else {
  if (relay_is_blacklisted($ip, 'sbl.spamhaus.org.')) {
    ...