netlupaLook up a domain's MX records
MX records say which servers receive a domain's email. Enter the domain to see them sorted by priority.
What is an MX record?
The MX (Mail Exchanger) record says which servers a domain's email should be delivered to. Each MX has a priority: sending servers try the lowest number first and, if it does not respond, move on to the next.
The MX names tell you who handles the email: aspmx.l.google.com is Google Workspace, *.mail.protection.outlook.com is Microsoft 365. If a domain has no MX, delivery is attempted to its A record, which almost never works.
Lookups by record type
Frequently asked questions
What does the number before the MX server mean?
It is the priority. The lower it is, the more preferred. If two records have the same priority, mail is spread between them.
My email isn't arriving. How do I check?
Make sure the MX records point to the right provider and also check the SPF and DMARC TXT records: if they are missing or wrong, messages may go to spam or be rejected.
How long does a DNS change take to propagate?
As long as the old record's TTL: from a few minutes to 24 or 48 hours. Nameserver (NS) changes usually take longer, because the TTL of the delegation in the TLD is high.
What does NXDOMAIN mean?
That the name you looked up does not exist in DNS: the domain is not registered, has expired or was mistyped.
Which DNS servers does this tool ask?
No middleman: Netlupa runs its own resolver, which starts from the root servers and asks each domain's official DNS servers directly.
Can I do a reverse DNS lookup of an IP?
Yes: look the IP up with the API (/api/dns/ptr/8.8.8.8) or use the WHOIS tool to find out who it belongs to.
Why do I see a different value than in my DNS panel?
Because resolvers still have the previous value cached. Wait for the time shown in the TTL, or check that you edited the zone at the provider listed in the NS records: if the domain uses other DNS servers, changes in your panel have no effect.
What is a record's TTL?
The time, in seconds, other servers may keep the answer before asking again. 3600 is one hour. A low TTL makes changes show up sooner, at the cost of more queries.