On Fri, 2010-06-25 at 15:29 -0700, Daniel B. Thurman wrote:
Are you talking about something like this from sendmail.mc:
FEATURE(`dnsbl', `relays.ordb.org', `"Rejected due to Open Relay see
http://www.ordb.org/lookup/?host=" $&{clientaddr} " for more
information"')dnl
Yes, that is a DNS Block List (DNSBL). So is Spamhaus. There are a lot
of them out there.
--Greg