e2003 can only send from the same domain as the domain controller

[user3657]

i have a few domains....
the win2k3 server is called mydomain.com
i can send and receive email fine from mydomain.com

i also have mydomain1.com, mydomain2.com etc etc.
i can only receive email from these other domains, if i try to send using them, it fails....exchange shows this error under queues: Unable to deliver the message because the destination address was misconfigured as a mail loop.

i do not host dns, i have free dns from everydns.net. all the domains are set with mx records, but like i said i can not send from the other names.

 

[user3657]

Im a dumbass, its because I had the outgoing stmp set as my isps server in outlook. Anyway I got everything to work but I have 2 questions:

1 what is the best way to secure exchange and not allow spammers to take over
And 2 is why couldn’t I send email without a smart host added, is that because I don’t run dns?

 

[rossthebossuk]

1. By default SMTP relay is disabled for anyone outside your network.
2. Yes you have to run DNS if you aren't using a smart host as Exchange uses DNS to lookup domain names.