MX lookup with provider identification
See which servers receive mail for a domain, in priority order, and which provider is behind them.
MX records name the servers that receive mail for a domain, lowest priority number first. They decide inbound mail only — changing them moves where your mail arrives, which is the single destructive step in any email migration. They have no effect on outbound sending, and nothing about SPF, DKIM or DMARC depends on them.
What does the priority number mean?
It is a preference, and lower wins. A sender tries the lowest-numbered host first and falls back to the next one only if that host is unreachable. Equal numbers mean “either, pick at random”, which is how large providers spread load. The numbers themselves are arbitrary — 10 and 20 are conventional but 1 and 5 work identically.
Do I need more than one MX record?
Not strictly. Sending servers queue and retry for several days when your MX is unreachable, so a single-host outage delays mail rather than losing it. A second MX shortens that window, and it matters most if your primary host has no redundancy of its own. Most hosted providers publish several already.
What happens if I change my MX records?
Inbound mail moves to the new servers as the old record's TTL expires — which is why any migration lowers the TTL a day in advance. During propagation some senders still use the old value, so mail arrives at both places. That is what a dual-delivery window is for: keeping a sync running from the old server for a week after cut-over, so nothing that landed there is lost.
Can I keep my mailboxes where they are and still send through another platform?
Yes, and it is the common case. MX governs inbound; SPF, DKIM and the Return-Path govern outbound. You can keep Google Workspace or Microsoft 365 receiving your mail while an email platform sends your transactional and marketing messages — you just add that platform's include to your existing SPF record rather than replacing it.