DNS, email and the MX-record (hosting a homepage, not the mail server)

Question

I have the following problem:

We are hosting a web site for a customer. So he changed his DNS A record to point to our virtual server. This works fine.

Now we created a new domain on our side with a standard dns-record for this domain via plesk (yeah, hit me ;) ). The logical problem is that we can't send emails with our company mail accounts to his email account because the DNS MX record (from our server) is also pointing to our server. (And our server responds, sorry no mail inbox here).

Is it enough to just delete the MX-record from our server? Or do I have to change more in the DNS records? I restarted the networking ("sudo /etc/init.d/networking restart") on our server, but we still can't send emails to him.

Thanks in advance! Matthias

Answer 1

You probably shouldn't be running a public nameserver; it requires basic networking skills and a decent understanding of DNS.

If you do not provide mail services at machine $X, then there should never be an MX record pointing at machine $X.

Answer 2

You should delete customers domain zone from your DNS server. Unless you have good reason not to do so (which you did not quite explain in original post).

Edit: Hosting customer site does not require that you also host their DNS zone. You mentioned that everything worked fine until you created DNS zone on your side, you should revert to that state. You could workaround by finding out correct MX record (by querying from outside of your network) and adding that MX to customers DNS zone hosted at your server, but that is highly unrecommended for many reasons.