What is an MX record?
An MX (Mail Exchanger) record is the DNS record that tells the world which server accepts email for a domain. When someone sends a message to jane@yourcompany.com, the sending server first looks up the MX record for yourcompany.com and hands the message to the server listed there. If the MX record is wrong or missing, email sent to you gets lost or bounces.
How to read the results
| Field | Meaning |
|---|---|
| Priority | Lower numbers are tried first, so a server with priority 10 is used before one with 20. Servers with equal priority share the load. |
| Target server | The name of the server that accepts the mail. It must be a hostname (with an A record), never an IP address. |
| Multiple records | If the primary server doesn't answer, the backup takes over. If the backup isn't filtered, spammers use it as a side door. |
Common MX record problems
- No MX record at all: some senders fall back to the domain's A record, but most will bounce the message.
- MX points to an IP address: this breaks the standard; the MX target must be a hostname.
- MX points to a CNAME: not allowed by the RFCs, and some servers will reject it.
- A leftover record from your old provider: forgetting to delete the old MX after switching hosts sends part of your mail to the old server.
- An unfiltered backup MX: if the spam filter only runs on the primary server, spammers use the lower-priority backup to bypass it.
How MX records relate to spam filtering
An email security gateway like Spambil works by having your MX record point to it. Mail arrives at the gateway first, gets scanned, and only clean messages are forwarded to your mail server. That's why setup is just one step: change the MX record. Your server, addresses and mail apps stay exactly as they are. After setup, you can use this tool to confirm the new record has propagated.
If you receive mail fine but the mail you send lands in spam, the problem isn't your MX record. It's SPF, DKIM or DMARC. Check your authentication records and read our guide on why emails go to spam.
Frequently asked questions
How long does an MX record change take to propagate?
It depends on the record's TTL. With a TTL of 3600, most servers see the new record within an hour. Lowering the TTL to 300 a day before the change speeds up the switch.
Do I need more than one MX record?
It isn't required. Sending servers keep retrying for hours if the destination doesn't respond. If you do use a backup MX, make sure it goes through the same spam filter.
Does changing my MX record affect outgoing email?
No. MX records only decide where email sent to you is delivered. Your outgoing mail keeps leaving from your current server.
Related: SPF, DKIM and DMARC explained · SMTP error codes · Email blacklist check