Our email server is Exchange 2003 in an AD network. Our spam filter is Trend Micro's ScanMail.
We are giving our sales reps a company email address and then forwarding all of it to their personal email address. To do this, we've been adding their external email address as a contact in AD, adding them as an AD user with an Exchange account, then all email sent to that user forwards to the contact.
This has been working fine, but they are signing up for spam using their work emails. And now, AOL keeps blocking us because we are forwarding some of that spam to them. Shouldn't AOL's mail server detect that we are not the original sender? Are there any suggestions as to how we could prevent this? I do believe that ScanMail is blocking some of it. It's just not doing a perfect job and it never will.
Update: I think my problem has been asked here. I missed that when I did my first search.
Why are you sending Spam to AOL? Or better: Why are you forwarding mails to AOL?
As you do send Spam to AOL they are totally correct to identify you as a Spam source. The only thing AOL can rely on is the IP that delivers mail to them. They don't rely on the Received line(s) in the message header. Why should they?
Is there any reason you can't give the remote guys OWA or even IMAP access to the Exchange mailbox (maybe over VPN if you are security-consious) and have them access their mail directly?
As for your issue, I don't think you're going to be able to stop AOL flagging your mail as spam. For all intents and purposes, you are now the sender of that spam, even if you are not the originator.
You may be able to remove the Exchange mailboxes for these users and use the 'Establish Email Address' to specify a SMTP account. In that instance, a truly RFC-compliant mail server might issue a
551 User not local; please try <forward-path>
message, and a compliant sending SMTP server might redirect, but I expect Exchange will just issue the250 Mail action accepted
or251 User not local; will redirect to <forward-path>
message and handle the redirection itself.