MX record setup: how mail routing fits together
MX records identify the mail exchangers responsible for receiving mail for a domain. They are part of the inbound mail path, while SPF, DKIM, DMARC, SMTP submission, and mailbox configuration solve different parts of email.
Use the mail provider’s exact MX hostnames
Do not point MX directly to an arbitrary IP unless the provider explicitly requires that design. MX values are normally hostnames, which must themselves resolve appropriately.
Priority chooses preference, not load percentage
Lower numerical MX preference is normally tried before higher values. Multiple records can provide fallback according to the receiving system’s design, but priorities should match the mail provider’s instructions.
Remove old routes only after the new service is ready
Create mailboxes or routing at the destination, verify required authentication records, and test before changing MX. During cache transition, old systems may still receive mail, so keep them available when practical.
MX does not control outbound authentication
Receiving mail successfully does not prove your sending setup is correct. Outbound mail still needs the appropriate SMTP service, identity, SPF/DKIM configuration, and deliverability checks.