Question : Cannot Get Exchange 2003 SMTP working

Please forgive my ignorance, I'm new to Exchange server.  

I have a domain registered with free parking, and my ISP is a different organisation, BT.  I have static IP address, assigned to Belkin router which is currently my DHCP server.  

I've built a new Windows 2003 sbs, with exchange server on it, and tried to get it to talk to the mail boxes associated with my domain.  I have changed the primary DNS setting for email on the domain to the fixed ip of my router, and the sbs box is talking to my router.  I have managed to get the POP3 stuff working (it seems, i.e. I've got it to stop erroring on port 110), but now it errors on port 25.  

What I am trying to achieve.  I want my sbs box to act as the mail server for my company, which I will connect MS CRM to.  If I point the smtp server setting to my ISP's smtp server it fails, telling me the email address is wrong - this is obviously to stop spammers grabbing my account, so how do i actually set my local box up to be the SMTP server?  I've tried all the default virtual servers, but am not wise in the ways of email servers, and help would be appreciated.  I know I'm getting the settings wrong somewhere.

I'm testing this using Outlook Express on the same box, to try and rule out network connection problems.

Fixed IP: 81.149.99.100
SBS IP: 192.168.2.100
Router IP: 192.168.2.1

SBS Box: NONONO-2003SRV

Error Message: Your server has unexpectedly terminated the connection.  Possible causes for this include server problems, network problems, or a long period of inactivity. Account 'nonono-2003srv', Protocol SMTP, Port 25, Secure(SSL) No, Error Number 0x800CCC0F

Many thanks

Answer : Cannot Get Exchange 2003 SMTP working

It could be possible, it is going to be a DNS checking problem. So however you have your SMTP connector to check for DNS resolution those are the settings you want to verify.