we're moving from a hosted zimbra to our own servers.
We have everything set up, with a new MX pointing to our new mail gateway, a new zimbra server and the restore procedure well tested.
The problem is: When we do the switch, the timing will be critical so no new mail gets into the old server. Typically, I'll add some mailertable-like rule so if mail gets into the old server, it'll be redirected to the new one (and I can use the old server as a backup MX just in case). The problem is: we don't have root access to the box, and the ISP is refusing to give it to us, or provide some sysadmin from their staff to do that tasks while we're migrating.
That leaves us thinking about some alternate ways to do that without their help.
Is there a way to do that redirection from within zimbra? (we only have the web access, not CLI access). Can I configure the domain in such a way a sender will try the new MX instead of the older one?
Thanks in advance