** Chris G cl@isbd.net [2009-11-03 18:49]:
I am moving my mail server from my desktop machine to a server machine. Both these machines are on my SoHo LAN behind a NAT router. Thus to move incoming mail from one to the other I have to change the port forwarding and firewall setings in the router.
Can anyone suggest a way to either send incoming mail to both machines or some other way of testing the new mail server before committing all my incoming mail to it?
I already copy all my mail to another user where it isn't sorted but just gets kept for seven days and then deleted. That is done on my hosting companies system. So I have some protection from total disaster! In addition of course the 'sender' (my hosting supplier) will wait and retry if/when I stop accepting mail so mail shouldn't be lost but I'd really like to do at least some simple testing before the big switch over.
** end quote [Chris G]
There's not enough detail of the nature of the setup to make specific suggestions, but one way you could use it to forward another port to the new machine. Then you can either telnet into the new port to test things out in a small way [1], and/or configure another domain/sub-domain to send mail into the new server [2].
Just a couple of ideas that sprung to mind. I have a selection of domains and full control of my external mail server configuration including a full shell (virtual server), so this is along the lines I'd look at. I'm in the process of doing this myself and will be doing something similar. For a while during the process I'll be routing mail through the old server and forwarding it on to the new one using hubbed_hosts (Exim 4), which may be something you could adapt as well - i.e. forward on a particular mail account perhaps.
[1] This either requires that you can telnet out through your connection and back in to the external port, or access to a shell session on an external computer (say work, or a suitable hosting account).
[2] This may be more than your setup can manage. It may not be possible to set a different port, or configure a sub-domain for mail, and you may not be wanting to purchase an extra domain for testing!