SBS 4.5 being used as staging server for e-mail

[Gerald]

I have a SBS 4.5 server running exchange for the e-mail services etc. My ISP has told me that he is getting loads of mail from my server. The mail is nothing to do with us. Our server is being used to forward the mail to recipients that are unknown to my ISP's server and they are clogging up his system. Does any one know what's happened and if so what to do to stop this happening. Thanks in advance.

[Wavey Davey]

Configure "Routing Restrictions" in Exchange Server. See:
http://support.microsoft.com/support/kb/articles/Q199/6/56.ASP
http://support.microsoft.com/support/kb/articles/Q196/6/26.ASP

[Gerald]

Cheers Wavey Davey, did just as you suggested and no more problems, funny thing was, I stopped the first server, and then another one from a different organisation started up doing the same thing, however, due to my new found technical knowledge I was able to solve the problem in double quick time.