MX or an A record

Dear all,

I get a bit confused by conflicting information between my boss and between my teacher. I hope somebody can give me a good argument why to use the one over the other:

Imagine we have the following network setup. In a network there are 2 mailservers with each a different IP address. Each mailserver has also a DNS server with the same IP as the corresponding mailserver.
If you want to e-mail from one mailserver to the other mailserver which DNS record should you provide?
-An A record from the one you want to mail and an MX record of you own mailserver.
-Or only an MX record of the one you want to e-mail.

I hope I'm a bit clear in the explanation if not please ask.
Your input would be very helpful

Gybium

Maybe I don't understand, but it sounds like you have 2 dns servers, each with their own mailserver. You want to mail from one to the other?

If this is the case, then you only need an A record and an MX record on each of the dns servers for each of the mail servers.

Your description is a little confusing, at least for me.

when it comes to mail flow and DNS records, you only need to make sure that you have the appropriate MX record in each domain (DNS zone). Of course, there should be an A record that exists to be able to resolve the alias that you have assigned as the MX record.

For instance, if you own domain.com, but host your mail at an ISP's site, you would have an MX record that points to mail.isp.com. Whoever hosts the isp.com zone, would have an A record for "mail".

However, if you also host the mail server, you would have an MX record that points to mail.domain.com, and you would have to host an A record that resolves "mail" as well.

hope this helps...

[JM], http://itgeared.com