domain name system - How to resolve proper mail server address from webhost with external DNS?

I'll try to be as clear and concise as possible, but it's a little confusing for me.

My company is currently hosting a website on a dedicated server. Normally we would maintain the DNS records, but the client for whom we are hosting has an external mail server they want to use and decided it would be easier to have an external DNS record. The final configuration looks something like this:

• The registrar points clientwebaddress.com to ns#.dnsrecordhost.com


• The DNS record host points to one IP (not ours) for mail and to another (our box) for web traffic


• Our box, by default, maintains DNS records on all domains hosted there

The problem is that we can no longer email our client @clientwebaddress.com because our web server is also our mail server and it's using its own records as authoritative. We've tried just disabling our DNS records but it doesn't seem to help.

Relevant webserver stats:

• RHEL 4


• Plesk 8.2

Let me know if I've left anything important out. Honestly we're in over our heads on this one. Any thoughts?

PS When I say "external" above I mean external to our webserver.

Answer

You mail server should be using the MX record to route the email. Configure an MX record locally for their domain, and point it to their mail server. It should be something like mail.example.com rather than example.com. You have have to duplicate their A record for their mail server.