Forward email for a domain to a new mail server for client

We have a client moving to a new email service provider and they have asked that we forward all email for their domain on our Virtualmin GPL server with Postfix to their server to prevent any downtime as the DNS records update. Is there a proper and/or simple way of setting this up so any incoming mail starts to relay to their new mail server while still allowing them to check email on our server during the transition? I seem to be searching the wrong topics or simply just not seeing the obvious solution. Any help would be greatly appreciated.

hi, I think you looking for this one?


it is possible to setup forwards for more then one emails in that window like

Also I think you can thick both deliver locally and also forward then out… but not 100% sure.

Thanks but actually I need to forward to the same email but on another server. So forwarding to I am reading that setting up a relay may be the solution here but still a little foggy on this.

hi, sorry for late reply, but had some work lined up. I think when you send email out and server is not reachable it should take something like 3 or 7 days to re-reach the server before it gets bounced completely…? - just my assumption.

What I would do (personally) is before set your new dns point, I would make sure that you change time for refresh of dns-es to 5 minutes or something like and then after at least 25 hours I would test it and if everything works - just change dns to point to new server and wait again at least 25 hours and then test it again to make sure it all works. Dns swap should take action in 5 minutes but 25 hours is still need it, to just test it and just to make sure it all works and for troubleshooting (if any need it, you still have day or so for this without any panic).

note: if everything works as it should (confirmed at least 5 times by checking test emails are actually really delivered on new server and not on your old server) - all emails gets delivered only to new server, I would change dns records for update time back to 24 hours or something sensitive you know, so dns server is not going to be hitting hard on refreshes etc… I hope so this does make some sense to you and it would help.

Thanks for the info. I believe this is about the only option here and likely the best practice. Thanks for your help.

you welcome oracast, im always happy to help if I can :wink: