Re: Strange SMTP errors...

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Author: Tom Samplonius
Date:  
To: Jawaid Bazyar
CC: exim-users
Subject: Re: Strange SMTP errors...

On Tue, 21 Jan 1997, Jawaid Bazyar wrote:

> Hi folks,
>
> I'm getting a whole rash of these, with exim 0.54..
>
>   rameen@???:
>     SMTP error from remote mailer after MAIL FROM:
>     <owner-afghanistan@???:
>     host wilbur.usa.net [192.156.196.9]:
>     503 Sender already specified

>
>
> What does this mean, exactly?


Somehow I doubt that Exim would send to MAIL FROM comands in row, but it
appears that wilbur.usa.net is a bit weird. For example if you do the
following:

mail from ...
rcpt to ...
data
(message here)
.

mail from ... <--- wilbur.usa.net give an error here

It claims that the sender has already has been specified. It is wrong
though, a sucessful message was sent, and according to RFC-821 the the
end-of-mail indication should "...consume the information in the reverse
path buffer (mail from), the forward-path buffer (rcpt to), and the mail
data buffer...". It is obvious that wilbur.usa.net does not consume these
buffers as it ought.

I always wondered why Sendmail always sends a RSET between each message.
I guess it is work around bugs in brain-damaged SMTP servers that need to
forced to forget information regarding the previous message. I suspect
that Exim 1.59 does this now, too.

<whine on>
There are far to many really-bad SMTP senders and receivers out there.
RFC-821 is only 68 pages, and clearly and simply written (as opposed to
RFC-822 which is overly complex). RFC-821 has also been out for 14
years!! I just don't get why so many interoperability problems and
bad, bad implentations still exist. I still run across that mailers that
don't accept "MAIL FROM:<>" (which almost always results in lost mail).
<whine off>


Tom