Fully Qualified Domain Names (FQDNs) may end with a final dot (e.g. www.example.com.).

I understand the final dot indicates a FULL domain, and name matching shouldn't be tried on assumed domains. (ie. do not try to match www.example.com.edu, even if sent from inside a .edu site that is configured this way)

But if I try to send to a valid email address via Gmail that ends with a final dot, I get the error:

The address "user@example.com." in the "To" field was not recognized. Please make sure that all addresses are properly formed.

Is Gmail correct in considering company-dot-com-dot improperly formed? Is this a Gmail error, or is there a reason that email addresses shouldn't use FQDNs that end with a final dot?

  • Just curious.. Are you really trying to send an email to an email that ends with a dot or you just accidentally left the dot in the end and got the error message?! – Lipis Feb 28 '12 at 2:00
  • I found this issue with a simple copy-paste (the address was at the end of a sentence, so I copy-pasted the final dot by accident). But I'm definitely curious if this is a gmail bug, or if they know something about email addresses that I don't. – abelenky Feb 28 '12 at 7:16
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    I'm guessing they never had an actual case that the email was ending with a dot, so instead of having that feature they decided to throw an error. – Lipis Feb 28 '12 at 10:04

It would appear that Gmail and now Outlook are going against some interpretation of the RFCs.

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