I am running sendmail version 8.13.1 under CentOS 4.4 . I am also running the greylist milter via a PL script as shown here:
I was using several dsnbl's and they blocked a ton of connections - and the first connect point.
The problem is that some of our customer and potential customers kept finding their way onto the lists, so we would block their mail without any warning or notice on our end.
So I would like to do two things, if possible:
1) Whitelist all known customers and have the dnsbl ignore (or not do) the online lookup if the customer's IP is in the whitelist. I think this can be done by the "spamfriend" feature in sendmail, but I have never used it before. One thing I do know is that I have to turn on FEATURE(delay_checks) to use this feature. What, if any, impact will this have on my greylist milter and/or mail server operation? I would assume we would have to spend more time connecting and getting all the mail info before we dumped the bad guys, but there could be other problems (to greylist?) from turning on the delaychecks option.
2) I would like to bypass all dnsbl checks for certain e-mail addresses (like email@example.com) so that no matter what, sales gets the mail even if the sending server's IP is on every known online dnsbl. Can this be done? This would let potential customer (not yet in the spamfriend whitelist) get mail to us even if they are listed.
So can these be done? Side effects of delaying the checks? And a simple how-to to show me for sure what goes where.