DNS - send received mail to two mail servers (mirror mail)

[SkyHiRider]

I've got two mail servers - old and new. I want to migrate mail bbut I need both servers to receive and store emails until I work out the bugs out of the new system.

If I add another MX record and set the priority to both of them it will randomize the process. I do not want load balancing, I want for every message received by the DNS to be mirrored and routed to both mail servers.

How can this be done?

[zombykillah]

Would say you've two or three possibilities:
Way1:
You install a tool that fetches the mails from server old into server new. (example: fetchmail)
Way2:
You create an automatic forward to the new server on the old one.
Depends on the software you had used on the old server.

Way3:
Set up a third "mail" software that forwards all mails to both servers.

If anyone knows another possibility I forgot, I wanna know 2!

[Lazydog]

Oh, and DNS does not receive any mail, that is not its job. Mail servers send a request to DNS for the ip address of the mail server. You should not be looking to DNS to fix this problem. As stated above setup your mail server to relay/copy the messages it receive to the new mail server.