On Thu, 22 Nov 2001, Gregory D. Rosenberg wrote:

> The . and <cr> issue you speak of is an outlook problem.  Outlook does not 
> encode attachments under certain circumstances properly and violates RFC 
> 822 standards.

Sorry, but no, this isn't an encoding problem, it's an SMTP problem.  It's
not an RFC822 problem- it's not the format of the message that has
the issue, it's the SMTP conversation (RFC 821) but it's a transport layer
issue, not an application layer issue, so 821 doesn't even cover it,
since it's a stack transport layer issue, not an application transport
layer issue.

> Most mail systems have added a patch to support and accept broken or 
> non-RFC 822

The DATA section of an SMTP conversation has to end in <CRLF>.<CRLF>- PIX
had problems with the . and final <CRLF> appearing in seperate packets-
it's a fairly typical packet filter state bug that's not an issue with
stack implementations like proxies and other mail servers because they get
a TCP stream, not individual TCP packets to work on.

> compliant mail attachments.  Imail, sendmail, postfix, as well as most 
> firewall vendors have addresses this issue.  But understand they are fixing 
> a Microsoft bug (failure to be RFC 822 compliant) not fixing their bug. 
> Cisco was slow in fixing this by comparison to others.  I happen to support 
> lots of PIXs and even though I might praise CyberGuard, we still are 
> predominantly a Cisco shop.

>From the fix notes:

20010529

 Workaround: old PIX firewall code messes up when the final
 ".<CR><LF>" at the end of DATA spans a packet boundary.
 When Postfix detects PIX SMTP fixup mode, Postfix flushes
 the output buffers before sending the final ".<CR><LF>".
 File: smtp/smtp_proto.c.

Quite obviously the SMTP code is generated by the MTA, not the MUA- so in
this case, Microsoft happens to be free of blame.

> 
> Cisco may have fixed the SMTP bug in the releases you state, but I will bet 
> they break it again in a future release.  This has happened two many times 
> now for me to think otherwise.

I'll take that bet.  Brian can cover me ;)

Paul
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Paul D. Robertson      "My statements in this message are personal opinions
[EMAIL PROTECTED]      which may have no basis whatsoever in fact."

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