Re: open relay exchange 2003
Hmm yes, stating the obvious you have configured an open relay mail server.
There are truly countless articles on how to configure your mail server correctly. Use :google: for your answers. (likely this forum has a lot of those too)
Also since exchange on default is NOT an open-relay you have made configuration changes which you have not told us about, and most likely made a slight config error. Perhaps you should also run the SBS internet and mail (?or something?) wizard so your mailserver is configured for you.
This is also very much recommended on a SBS-server.