Network with about 250 nodes, ISA Server 2006, Exchange 2003... users are getting a lot of spam. I have Intelligent Message Filter running and an Untangle (open source) firewall device supposedly blocking a lot of spam.
I think I have a machine on the inside of the network possibly sending out the spam inside the firewall. Two Questions:
1) Anyway or any utility I can use to find this possible culprit short of going desk to desk?
2) Can I use Group Policy, ISA Server or any other tool on the network to block any SMTP traffic except that which is generated by the Exchange Server?
... I am open for suggestions... users are getting tired of wading through the BS spam.