Email::Valid does this; for domains or as a part of validating addresses: "mx ( <ADDRESS>|<DOMAIN> ) This method accepts an email address or domain name and determines whether a DNS record (A or MX) exists for it."

perl -MEmail::Valid -le 'print Email::Valid->mx("gmail.com") ? "yep" :
+ "nope"'
yep

perl -MEmail::Valid -le 'print Email::Valid->mx("tacohut.co.uk.jp.cx")
+ ? "yep" : "nope"'
nope

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In reply to Re: Determine if domain is actually used for email by Your Mother
in thread Determine if domain is actually used for email by vit

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