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Hi folks,
I'm running Exchange Server 2007 Beta2 on my W2K3 machine (and before you all say it, yes, I know it's not supported in production environment but it's the only way I've found so far to get a free Windows mail server).
It's set up with Hub Transport, Client Access and Mailbox roles (I don't have an additional computer that I can run Edge Transport on - yet - and again, I know it's far from recommended to have a HT server sat right on the Net).
I'm having massive problems with my server being used to relay spam - and as I'm using a smarthost (which I pay an annual fee for) I only get 300 mail relays per day which the spam is swallowing up. I've set up a Transport Rule which should stop the spam - basically it reads "if the mail is from outside the organisation, to people outside the organisation, then drop the message, unless it's from or to people or distribution lists inside the organisation".
This should drop all messages that are attempted to be open-relayed - but it's not working.
I'm now investigating a) getting a second computer on which to install Edge Transport, b) blocking all dynamic IP addresses from relaying mail through my server, or c) investing in the full release of Exchange Server with all it's features (including built-in antispam agents, both for Hub Transport and Edge Transport).
I think that a) or b) is the most cost-effective for me but I need to know where can I get a list of dynamic IP blocks that ISPs assign to users, so I can then load this list into an IP Block list in Exchange?
Or (if anyone can fathom it) why are my Transport Rules not working effectively?
Many thanks in advance,
medicineworker
