sendmail and DNS

[Jangalwa, Raj]

Hi Gurus,

I am building a preimary DNS with 8.1.2 bind for a new site. Can someone
direct me on how to put entries on my DNS server for the mail servers.

For ex. my DNS is for the domain "testdomain.com" and I receive mail from
two domains 1) someone at testdomain.com and 2) someone at testdomainmail.com.
and my mail server is "mailserver.testdomain.com" with a valid IP address
inside the firewall.

Now how should I configure my DNS so that any mail coming to
"someone at testdomain.com" and "someone at testdomainmail.com" gets send to
"mailserver.testdomain.com".

Thanx in advance and will summarize

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Raj Jangalwa