Explain step by step how to send extrernal emails using exchange 2003 server

You will need to make changes to your MX recods in the DNS server. For example you have a website called mywebsite.com whose e-mails were handled by the ISP server domain myisp.com. Update myisp.com mx record to your new mail server FQDN.

Best, Nauman

In the instance mentioned above I think it is assumed that you either:

Have a public gateway e-mail server
Have a firewall that is performing some sort of address translation

In either instance you are going to have to make sure that whatever device is catching traffic on the outside public interface (that would get designated in you public MX record) knows how to get to the internal server.  Are you currently behind a firewall?  If so what kind?

Crow

I am behind a firewall (Symantec Gateway Security 5420) that redirects smtp and POP3 traffic to the exchange server. Do I have to update my MX records for the firewall or for myisp.com. I want to use the POP3 server provided from our website host to login and receive email and I want to use our exchange server to send out external email. Now I am using the outgoing sever of our ISP to send out email. Basically the only thing I want to do is replace the current outgoing server with our own exchange server. We have problems using the ISP's outgoing sever and we want to use our own exchange just to send out email. Like I said I m not very familiar with exchange so can you tell me how to update the MX records? Thanks for your help.

Hmmm.  I just want to clarify that you are looking for a solution that:

Allows you to freely send e-mail from your Exchange server to the outside world
Keeps your inbound (pop3) e-mail on the ISP server for storage and accessability

If this is the case you don't need to make any changes to your public MX record as it is already telling any incoming e-mail exactly where it needs to go.  Are you running DNS in your enviroment?  If so is it set up with forwarders pointing to your ISPs DNS servers?

The next thing to verify is that DNS is configured correctly on your Exchange server and that port 25 on your firewall is open for any traffic originating from the ip address of the exchange server.

This is exacty what i want to do. I have to tell you that the inbound POP3 server belongs to the company that hosts our website which is different from our ISP (the outbound server though belongs to our ISP). One company handles our incoming email and another our outgoing. So I just want to replace our outbound server with our exchange server to only send out email. Port 25 is open on the firewall for 2 way traffic. I am running DNS...so should the forwarders be pointing to my ISP's servers or not? Right now I don't think they are pointing to any external dns servers. Is this all I have to do? Do I have to set up some kind of smtp connector or not. Thanks

If you are using forwarders on your network they should be pointed to the DNS servers that are hosted by your ISP.  This will increase DNS resolution performance.  I'm betting that this is all you have to do.  The way it works is:

Exchange ask DNS where to find joeuser@microsoft.com
Internal DNS asks the ISP DNS where to find juser@microsoft.com
ISP DNS gives internal DNS the mx record info for microsoft.com
Internal DNS tells Exchange where to find juser@microsoft.com

Make sure that Exchange is pointing to your DNS server once the forwarding is set up.

Hope this helps
Crow