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What is e-mail spoofing?


If you are getting returned e-mail that appears to have come from an address you do not have setup,
you may be the victim of e-mail address spoofing.

E-mail spoofing is the use of someone else’s e-mail address when sending messages. This does not
necessarily mean that someone used your e-mail account. The header information for the e-mail will
contain the name of the server that actually sent the mail. 1&1’s outgoing mail server is mout.perfora.net.

For example, you may get a message saying “Could not deliver message.” And when you look at the
details, it appears the mail has come from some_random_name@yourdomain.com. But you do not have
this address set up.


How could someone use this to send e-mails?

The SMTP protocol allows you to specify any e-mail address in the “From:”, “Reply To:”, and
“Errors To” headers. This is the address that a failed delivery will be returned to.


Will my domain be blacklisted because of this?


The simple answer is, it shouldn’t. Blacklisting is usually done on the server level, not
the domain level. So the mail server receiving the spam should look at the actual mail server
the mail came from, and blacklist only that mail server’s IP address. If you believe your domain
is being blacklisted, please contact technical support, and we will assist you in resolving
that issue.

* It may be a good idea not to use “catch-all” e-mail addresses if your domain has been used in
spoof e-mails, as this will become a receptacle for all of the bounce-back messages for e-mail
addresses that were spoofed.


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