Fromheader isn't resolvable.
While this might prevent some folks from being able to get email
in, we've taken the step because experience has shown that in
the cases where the
From header in the envelope
doesn't resolve, this is the result of either intentional
forgery or a misconfigured mailhost.
From:header that you see in the email, but rather the
Fromheader that mail transfer agents (MTAs) use as the ``control address''. Please have your local system administrator fix your email such that your mail's envelope will contain fully qualified domain names (FQDNs) where applicable. (This is really something that should be done anyway.) We apologize for the inconvenience.
What's most likely happened is that mail to someone here arrived
at our gateway with a header in the form of
user@host instead of a globally-resolvable
email@example.com. If this is the case, a bounce
message would return to your user with an error message like:
451 <user@mailhost>... Domain does not resolve - see http://www.interhack.net/projects/spam/resolve.html for details and help.This means that your mail relay is identifying itself as
mailhost.your.domain. How this is fixed will depend on your mail transfer agent and your own DNS. Given that this is very site-specific, we can't provide any more help about host configuration.
Certain mail user agents (MUAs) like Netscape, Eudora, etc.,
that want to use an ``SMTP host'' to deliver outgoing mail will
write their own SMTP envelope. They'll do this by taking the
value that the user provided as their email address (which will
appear in the message's
From: header and using it
in the SMTP envelope
A mail transfer agent, configured to use the user's real
email address, should be able to send mail to us without
For more information, please see Why Spam Sucks for a more detailed discussion about why spam is bad for everyone.