Re: [EXIM] Empty MAIL FROM

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Lähettäjä: Greg A. Woods
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Vastaanottaja: exim-users
Aihe: Re: [EXIM] Empty MAIL FROM
[ On Fri, November 28, 1997 at 14:43:19 (+0000), Philip Hazel wrote: ]
> Subject: Re: [EXIM] Empty MAIL FROM
>
> On Fri, 28 Nov 1997, Mike Zanker wrote:
> >
> > I've just noticed that when Exim is sending a delivery error report it uses
> > a blank envelope from address (MAIL FROM:<>). Is this intentional?
> >
> > Some mail hosts are rejecting them because of this (sprintmail.com MX hosts
> > for example).
>
> Those hosts are broken. From RFC 1123:


However it may be more interesting than that. They're not actually
rejecting until after the first RCPT TO: command is sent, which seems
exceptionally silly to me, though they may have found some strange
reason to do this, such as supporting extremely broken mail clients:

00:42 [26] $ telnet mailgate21-hme0.a001.sprintmail.com 25
ksh: exit code: 1
Connected to mailgate21-hme0.a001.sprintmail.com.
Escape character is '^]'.
220 mailgate21-hme2 SMTP Ready.
HELO most
250 (most) pleased to meet you.
MAIL FROM:<>
250 <>... Sender Ok
RCPT TO:<postmaster>
553 Both To: and From: must be in form of: user@domain
quit
221 Closing connection
Connection closed by foreign host.

00:43 [27] $ telnet mailgate21-hme0.a001.sprintmail.com 25
Trying 205.137.196.52...
Connected to mailgate21-hme0.a001.sprintmail.com.
Escape character is '^]'.
220 mailgate21-hme2 SMTP Ready.
HELO most
250 (most) pleased to meet you.
MAIL FROM:<>
250 <>... Sender Ok
RCPT TO:<postmaster@???>
553 Both To: and From: must be in form of: user@domain
quit
221 Closing connection
Connection closed by foreign host.

[And I thought it was draconian to reject invalid HELO's! Sprintmail
has really gone overboard! ;-) How many will follow?]

Actually I can sort of see their point. Not accepting bounce messages
keeps everyone in the dark and probably cuts down a whole lot on the
number of messages their postmasters have to deal with! :-)

-- 
                            Greg A. Woods


+1 416 443-1734      VE3TCP      <gwoods@???>      <robohack!woods>
Planix, Inc. <woods@???>; Secrets of the Weird <woods@???>


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