I have an x64 box running Exchange 07. In front of it I have a spam server running MailScanner off Ubuntu. Typically when the linux server bounces something and I add it to the white list, when it tries to relay to Exchange, Exchange then bounces it back to the spam server. Whenever this has happened in the past, I simply added the mail servers coming in on that bouncing domain (it comes in blocks of entire domains, for all intents and purposes here) to the BypassedSenderDomains list and then it went through fine.
Now I have found one domain that this doesn't work on. The incoming mail, I see when I grep for the domain in the mail.log, is bouncing off of at least 5 different servers, usually 3-4 per email before it gets to the spam filter. The filter then white lists and passes to Exchange, but even though I have added all 5 servers to the BypassedSenderDomains list, Exchange continues to bounce these messages back to spam.
Anyone have an idea? I'm fresh out and could use a hand.