Moving email without downtime (MX switch, running in parallel)
What you need
- Access to the control panel of your domain, where you adjust the DNS and MX records.
- Your old mailbox (address and password) and your new Mailflux mailbox on your own domain.
- The server settings: IMAP on port 993 with SSL, SMTP on port 465 with SSL. The Mailflux server name can be found in your Mailflux account or on IMAP and server settings.
- The correct MX values from Mailflux for your domain.
Moving email without downtime: step by step
- Get your new mailbox fully ready on your own domain and copy your messages to it in advance. How to do that safely, you can read at moving email without loss.
- Lower the TTL of your MX records a day beforehand (for example to 300 seconds). That way servers pick up the change faster and the transition is shorter.
- Test your new mailbox thoroughly: send and receive a few test messages via both the webmail and your mail program.
- Switch the MX records to the Mailflux values. The exact steps are at setting up MX records.
- Run in parallel. Keep your old mailbox open while the change spreads. During this period new mail can still briefly arrive on the old server; so check that one too.
- Copy over late messages. If messages did land in the old mailbox during the transition, copy them over to Mailflux as well.
- Wrap up once all new mail arrives reliably at Mailflux. Only then do you clean up the old mailbox.
Why you don't miss anything here
The MX switch moves nothing, it only sends new mail to a different place. Your old messages are already safely copied to Mailflux, and your old mailbox stays reachable for a while after the switch. Because you run in parallel, there is no moment when mail has nowhere to go. Email never gets "lost" between two servers: if a server is briefly unreachable, the sending server simply tries again. The lowered TTL from step 2 keeps the window in which this plays out as short as possible.
Not working?
- New mail still arrives on the old server. That's normal right after the switch. Keep the old mailbox open until everything has spread (sometimes up to a day).
- The MX change doesn't seem to take effect. Check that you've replaced the old MX records and not left them alongside the new ones, and that there's no typo in the values.
- Sending or receiving on the new mailbox stutters. Check that you're using port 993 with SSL (incoming) and port 465 with SSL (outgoing) and that the server name is correct.
Done, and need help?
If all new mail arrives reliably in your new mailbox, the move has succeeded and you had no downtime. Only clean up your old mailbox once you're sure of that. Want to set the MX records exactly right? Then follow setting up MX records step by step. Rather not tinker yourself? Feel free to let us handle your migration: we'll help you on your way personally.
FAQ
Frequently asked questions
Will I lose messages during the MX switch?
No. A sending server that doesn't yet see your new address automatically tries again, often for hours. And because your old mailbox is still open, late mail is caught there and you copy it over. By lowering the TTL beforehand, you keep the transition window short.
How long does it take for the MX change to be active everywhere?
Usually it's done within a few hours, sometimes up to about a day, depending on the TTL that was set on your records. If you lower the TTL a day beforehand, it goes faster. Until then, keep your old mailbox open, so you definitely don't miss any messages during the transition.