Mailing List Archive

VRFY and EXPN issues
John C. Ring, Jr. <> writes:
>Greg Andrews <> wrote:
>>In my opinion, EXPN and VRFY are excess interactions that don't
>>contribute to the overriding goal of an MTA: Transporting E-mail.
>>Any information about whether a host can deliver to an address can
>>be found in the response to the smtp "RCPT TO:" command. EXPN and
>>VRFY are unnecessary to the actual transport of mail, so a mail
>>transport agent shouldn't be required to support them.
>Nevertheless, there are, I have found, times where this extra feature
>is *very* useful from an administrative point of view.

Yes, that's very true.

My point was that the benefits of having EXPN and VRFY available to
administrators (and other responsible users) are starting to be
outweighed by the drawbacks of having them available to malicious
users. That's why I think things like Sendmail's 'noexpn' and
'novrfy' options are signs that the Internet is abandoning EXPN
and VRFY.

Greg Andrews West Coast Online
Unix System Administrator 5800 Redwood Drive Rohnert Park CA 94928
(yes, 'greg' backwards) 1-800-WCO-INTERNET