I have a POP3 connected exchange server in windows small biz server that is having issues downloading messages larger than about 2 or 3k.
Its been service packed to SP2 for exchange, the server was working just fine till the client updated thier DSL circuit. Nothing else has changed. They can surf the web and ISP states they are not blocking any ports. An Outlook client that is pointed to the ISP has the same issue. We have set the DSL modem to point to the sonicewall firewall to be the DMZ in addition to setting specific rules for the the various ports: 3389, 4125, 25 etc.