Re: fingering e-mail addresses

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#52

From: Tollef Fog Heen
Date: Sun, 05 Sep 1999 00:00

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distler@golem.ph.utexas.edu (Jacques Distler) writes:

> There's no way to disable *that* without breaking SMTP (which is why only
> a bozo would disable VRFY).

There was a discussion regarding this on bugtraq some time ago, where
spammers had used exactly this method of gathering addresses. Also,
note RFC 1123:

      5.2.7  RCPT Command: RFC-821 Section 4.1.1

         A host that supports a receiver-SMTP MUST support the reserved
         mailbox "Postmaster".

         The receiver-SMTP MAY verify RCPT parameters as they arrive;
         however, RCPT responses MUST NOT be delayed beyond a reasonable
         time (see Section 5.3.2).

         Therefore, a "250 OK" response to a RCPT does not necessarily
         imply that the delivery address(es) are valid.  Errors found
         after message acceptance will be reported by mailing a
         notification message to an appropriate address (see Section
         5.3.3).

So you can't be _sure_.

-- 

Tollef Fog Heen
Unix _IS_ user friendly... It's just selective about who its friends are.

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<37CB6A34.7178@cygnus.uwa.edu> <7qqnji$q2l$1@lios.apana.org.au> <37d985c4.7783654@news.earthlink.net> <distler-0409992051420001@192.168.0.1> <37D21508.6828@cygnus.uwa.edu> <distler-0509990250210001@192.168.0.1>

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From: Tollef Fog Heen <tollef-news@add.no>
Subject: Re: fingering e-mail addresses
Date: 1999/09/05
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