Multiple MX Records Explained (And Why You Should Not Mix Providers)
Priority values, backup MX, and the danger of leaving old MX rows during migration.
MX records tell the internet where to deliver mail. Duplicate or conflicting MX rows split delivery between hosts — the most common migration mistake.
How MX priority works
Each MX records (the settings that tell the internet where to deliver email for your domain) has a priority number. Sending servers try the lowest number first and only use higher numbers if the first is unreachable. Two records with the same number share the load. The numbers are relative — 10 and 20 behave exactly like 1 and 2.
Why mixing providers breaks mail
If you leave your old host’s MX record next to the new one, some senders will deliver to the old host and some to the new one. Mail looks randomly missing, and it is hard to diagnose because nothing bounces. When you migrate, replace the old MX records instead of adding to them.
Do you need a backup MX?
Usually not. Sending servers already retry for days when your host is down, so mail is queued rather than lost. A backup MX run by a different company must also know which addresses are valid and apply the same spam filtering, or it becomes an easy route for spam. OquMail gives you a single MX records (the settings that tell the internet where to deliver email for your domain) at priority 10; use only that.
Quick check
nslookup -type=mx yourdomain.comWant to see how your own domain is set up? Use the free MX lookup: it runs in your browser and stores nothing.