Help with Exchange 2003

Hi,

We recently configured exchange 2003 and everything was working fine until a couple of days ago, all of the sudden our server got bombarded with tons and tons of bad emails. We normailly have about a couple hundred badmail a day but now we get about a couple hundred thousand a day. In addition, we are getting more 5mb (mdbdata directory) log files than usual too. I have to clean out these directory on a daily basis now because its taking up space. I’ve checked out some of these messages and they are all spams with incorrect address. How can I put an end to all of this?

Currently I’m trying the filter option within exchange to see if I can filter out some of the sender. Any help in resolving this issue will be greatly appreciated. Thanks in advance!