MX Lookup: Where Your Email Goes
Enter a domain or an email address. See its mail servers in the order senders try them, their addresses, the provider, and what to fix. Free, no sign-up, nothing stored.
Your Domain
Try it: salesforce.com, example.com
How Email Finds Its Way
Four steps between Send and the inbox. The MX record decides the second.
- 1
The Sender Reads the Domain
Everything after the @ in the recipient’s address.
- 2
It Asks DNS for the MX Records
Each names a mail server and a priority. The lowest number is tried first.
- 3
It Delivers, or Moves On
If a server doesn’t answer, the sender tries the next one, and keeps retrying for days before it gives up.
- 4
The Receiver Checks the Sender
SPF, DKIM and DMARC of the sending domain decide whether the message lands in the inbox, in spam, or nowhere.
MX, SPF, DKIM, DMARC: Which Does What
Only MX is about mail coming in.
| Record | What it says | Direction | Where |
|---|---|---|---|
| MX | Which servers receive mail for the domain | Incoming | The domain itself |
| SPF | Which servers may send with the domain in the return-path | Outgoing | The domain (TXT) |
| DKIM | The public key that checks a message’s signature | Outgoing | selector._domainkey (TXT, CNAME) |
| DMARC | What receivers do when SPF and DKIM don’t match the From address | Outgoing | _dmarc (TXT) |
Common MX Problems
What the lookup flags and how to fix it.
- MX points to a CNAME. Not allowed for MX targets; most senders cope, some don’t. Fix: name the final host instead.
- MX points to an IP address. An MX must name a host. Fix: create a host name with an A record and point the MX at it.
- MX host without an address. Often a typo or a server that was switched off. Fix: correct or remove the record.
- Two providers in one set. Left over from a move, so some mail lands in the old mailbox. Fix: remove the old provider’s records.
- No MX at all. Senders fall back to the domain’s own address. Fix: add MX records, or a null MX if the domain receives no mail.
- A sending-only domain without null MX. Replies and bounces to it wait in queues for days. Fix: publish MX 0 “.”.
MX Records and Salesforce Email
Setting up Account Engagement (Pardot) or Marketing Cloud Next never asks you to change your MX.
- Pardot Sends Without Your MX. Its return-path is a Salesforce bounce domain, so bounces never reach your mail server. Salesforce Help 000381338 (opens in a new tab)
- Marketing Cloud Next Brings Its Own. Bounces go through the bounce CNAME Salesforce gives you; none of its eight records is an MX. Salesforce Help 004576430 (opens in a new tab)
- Replies Still Need a Mailbox. People reply to your reply-to address. Check that its domain has working MX records.
More Free Tools
MX Lookup FAQ
Short answers to what people ask about MX records and email routing.
What is an MX record?
A DNS record that names a server receiving email for a domain, with a priority. A domain can have several; senders try the lowest number first.
How do I look up MX records on the command line?
dig MX example.com or nslookup -type=MX example.com.
What does MX priority mean?
The order senders try the servers in: lowest first. Equal numbers share the load at random.
What happens if a domain has no MX record?
Senders deliver to the domain’s own address (RFC 5321). If there is none, mail bounces. A domain that should get no mail publishes a null MX: 0 “.”.
What are the MX records for Google Workspace?
Google’s current setup is one record: smtp.google.com with priority 1. Older domains use five ASPMX records, which still work; don’t mix the two.
Does Pardot need an MX record?
No. None of the records Salesforce lists for a Pardot or Marketing Cloud Next sending domain is an MX record. Your reply-to address needs a domain with working MX records, as for any email.
How long until an MX change takes effect?
As long as the old record’s TTL, shown in the result. Senders that cached the old answer use it until then.
Is the domain I look up stored?
No. Your browser sends the names to our server, which asks a public DNS resolver. Nothing is saved, no domain is logged, and the resolver never sees your IP address.
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