I agree, it is best to have the secondary/scanning server know what accounts are real or not, but this isn't always practical to enforce.
Still, in the case that the secondary does attempt delivery to a non-existent account, as long as it's already decided that it's not a virus, the mailbox that it'll be sending the bounce message to is much less likely to be a forged, and valid, address... and this is what Spamcop is really trying to stop: Bounce backs, predominately from virus' that forge the sender using a randomly chosen, but real, address. Eliminate the virus, and you eliminate the majority of the problem. Bill Healy wrote: >But if there is a secondary or virus scanning only server that is a >relay for another server it has no way of knowing which accounts are >valid and it will accept all mail for handled domains. Then when the >secondary MX or virus scanner tries to deliver the message to the >primary mail server it will at that point find out if the mail is to a >valid account. If it's not valid then the server trying to make the >delivery will generate a bounce message back to the sender, that's the >problem spamcop is trying to stop. > >The load on my spam and virus scanning servers that front end for other >mail servers has significantly decrease now that I verify who the mail >is going to before any spam or virus scanning. I'm not using xmail as my >front end server for scanning, I'm using a dedicated server with >MailScanner http://www.mailscanner.info/ to scan for virus, spam, >phishing, banned attachments, among other things before being passed on >to the Exchange and xMail servers. > >Bill > > > >>Bill Healy wrote: >> >> >> >>>If so then maybe you should look into a filter that can validate >>>delivery addresses before accepting a message. >>> >>> >>> >>> >>> >>> >>I would think that just doing virus scanning in a post-data filter on >>the secondary MX should be enough to limit a good majority of >>misdirected bounces that would actually hit a live mailbox. Perhaps SPF >>would catch much of the remainder? >> >> >> > > - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
