Can't send mail from exchange to smpt and ISP not helping

A client of mine moved their domain to another ISP due to the old one having major down time issues.

Now they have a reliable ISP that has a good up time record but they are having problems with email.

They use Exchange Server 2003 Small Business Edition. We have managed to get the pop3 working so they can now retrieve email, but each pop3 account on the new ISP has its own smtp login and exchange required one user name and password to authenticate?

The ISP is not being helpful at all saying we shoudln't need to use exchange, just outlook. Is there a solution to fixing this and is it a case of moving to another ISP?

I need to be clear in some point before give you any solution.
1st, what is the MX of your Domain? ISP's mail server ? or your Echange's IP? Where is your POP account running? In ISP server? Seems that your domain MX point to ISP's mail server. In this condition, ISP's mail server is receiving mail from internet and deliverying to POP account.

If his is your situation, you don't need to use your exchange at all! just collect the SMTP server address from your ISP and put it to your clien's outlook setup, it should work. Or of you want to run your system in old way, make sure that your domain's MX is pointed to your Exchange server IP. All should run normal.

One more thing, make sure that your ISP is not blocking your incoming 25 port to exchange, or nothing will work at all..


Have Fun!~

Ahamed Bauani
http://www.bauani.org/

Ahamed is right, your ISP needs to setup an MX record to the IP of your Exchange box (it would be really cool if they would NAT to an internal IP for you too so you don't need to expose your Exchange box but they probably won't do that). Basically, if they are any good at all it should only take an admin 5 mnutes to set that up. If they won't do it I would find one who will (and while you're at it, ask if they would consider NATing to an internal IP addy for you (unless you can do that on your end in the router).