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Search Domain DNS MX records,email mx records check,mx record lookup

This is free online tool for check MX records (lookup) for domain or check e-mail (and find MX records for e-mail). MX record search going according to RFC recommendation. So just input domain/hostname or e-mail (email) address and push "Go". If you want do dns lookup A and MX a record, fetch dns a mx records, find a and mx records you can use custom domain info tool - it's fecth all DNS records (A,MX, and many others)
RFC2821 (before mail sending): Once an SMTP client lexically identifies a domain to which mail will be delivered for processing, a DNS lookup MUST be performed to resolve the domain name. The names are expected to be fully-qualified domain names (FQDNs). Local nicknames or unqualified names MUST NOT be used.
This test will list MX records for a domain in priority order. The MX lookup is done directly against the domain's authoritative name server, so changes to MX Records should show up instantly. You can click "Go" for connect to the mail server, verify reverse DNS records.
Short for mail exchange record, an entry in a domain name database that identifies the mail server that is responsible for handling e-mails for that domain name. Single domain can have more than one MX record.
mx record lookup fast link: or (https://my-addr.com/mx/yahoo.com)

[www.domain.com] it's subdomain of [domain.com]. Thats why [domain.com] can exist but [www.domain.com] not exist and [www.domain.com] can exist but [domain.com] - not.
As usualy mx records don't exist for subdomain [www.domain.com], thats why useful to do mx record lookup and email check for domain (hostname) without 'www'
new window:
yahoo.com (example of lookup)

IP 98.137.11.164
IP 174.6.143.25
IP 274.6.143.26
IP 374.6.231.20
IP 474.6.231.21
IP 598.137.11.163
COUNTRY NAME United States
REGION NAME CA
CITY Sunnyvale
PROVIDER (ORG) N/A

MX records

MX 1 mta7.am0.yahoodns.net
MX 2 mta5.am0.yahoodns.net
MX 3 mta6.am0.yahoodns.net