[NTLUG:Discuss] verifying delivery to a specific recipient wi th sendmail

[Gregory L. Camp]

Well, unfortunately many MTA's don't support/enable the VRFY (verify)
command.  That is *supposed* to let you know if a particular address is
valid.  However, since a would-be spammer could use that same command to
garnish "real" email addresses, most security people recommend your MTA not
enable that feature (ours at the office doesn't).

So, in short, without sending a real test message, I'm not aware of any way
to check the validity of any given email address.  Sorry!

Greg

> -----Original Message-----
> From: David Camm [mailto:bbai at onramp.net]
> Sent: Wednesday, April 11, 2001 8:07 AM
> To: discuss at ntlug.org
> Subject: [NTLUG:Discuss] verifying delivery to a specific 
> recipient with
> sendmail
> 
> 
> all the forms processing transactions i've written in perl use the
> following pattern to check the validity of the FORMAT of an email
> address:
> 
> /\w+((\.|\-)\w+)*\@\w+((\.|\-)\w+)+/
> 
> this works quite well to ensure that the address is of a reasonable
> form.
> 
> of course, users will make all sorts of other errors when 
> entering their
> address, which a pattern cannot catch.
> 
> i've been trying to find a way of using sendmail to actually attempt
> delivery and capture that result. after poring through the bat book
> (makes a great doorstop) and the man pages, one discovers the -bv
> switch, which, it is claimed, will verify delivery of a message.  when
> one tries this as in:
> 
> [root ~]# /usr/sbin/sendmail -bv foobar at hotmail.com
> 
> sendmail responds that the address is deliverable like:
> 
> foobar at hotmail.com... deliverable: mailer esmtp, host 
> hotmail.com., user
> foobar at hotmail.com
> 
> apparently, the definition of deliverable is to the target MTA, not to
> the user.
> 
> i'd like to save my customers some aggrevation and reduce the 
> number of
> e-mails bounced back to root.
> 
> does anyone know how a delivery test to the intended 
> recipient might be
> done?
> 
> thanks! 
> 
> david camm
> advanced web systems
> www.advwebsys.com
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