Lukas Beeler’s IT Blog

I’ve seen many people losing mail when changing MX records, for example when you switch from POP3 Retrieval to direct SMTP retrieval.

It’s rather simple to change MX records correctly, though there are some administrative hassles involves when you don’t have your own DNS servers. But the procedure can still be used, just ignore all the things about POP3.

If you control both mail exchangers, the whole thing is extremely easy

• Change your TTL to a small value. 5 Minutes is a good start. Note that you can change either the TTL of the MX record itself, if you change the Name, or the TTL of the A records the MX records points to, if you’re changing the IP address, and the MX keeps the same name
• Wait till your old TTL has expired. Note that with a default TTL of 86400, this means you will have to wait a day.
• Make sure the new MX is running, then change the MX record (or the A IP address). If you’re switching from MX to MX, now is the time to add an SMTP route
• Wait 5 Minutes, then retrieve your mails from POP3, this step ensures that no mail is lost for sure
• Change your TTL back to a sane value. If you’re a low traffic site like a SMB business, i recommend a TTL of 1 hour, 3600s. This makes it easier for future changes.