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From: rich@GATEWAY.MITRE.ORG (Richard Verjinski)
Newsgroups: comp.protocols.tcp-ip
Subject: (none)
Message-ID: <9008061918.AA16065@gateway.mitre.org>
Date: 6 Aug 90 19:18:30 GMT
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From: primerd!ENI!S61!JB@bloom-beacon.mit.edu
Subject: An SMTP Question

>From: primerd!ENI!S61!JB@bloom-beacon.mit.edu
>I have an SMTP implementation that may or may not have a problem concerning
>null characters in the mail data.  RFC 821 states that the mail data may
>contain any of the 128 ASCII character codes.  This statement implys that
>the null character must also be handled as mail data.  Is this correct.

>I spoken with some people about this and they do not know of any implementation
>that supports this.  We have a customer who feels this is a problem.  The
>mail text with a null will truncate that line of the mail data since we
>are using C string functions.  Any comments or pointers will be appreciated.


The MIL-STD-1781 SMTP specification shows the BNF for an SMTP string on
page 20. 

  <string> ::= <char> | <char> <string>
  <char>   ::= <c> | \<x>
  <c>      ::= any of the 128 ASCII characters, but not any of the <special>
               or <sp>
  <x>      ::= any of the 128 ASCII characters (no exceptions)
  <special>::=  ... the spec shows all the characters and also says:
                (ASCII codes 0 through 31 inclusive and 127)
  <sp>     ::= the space character (ASCII code 32)

From this information I think that it is safe to say that the NULL
character can be passed as data, but must be preceded by the "\"
character.

Anybody disagree?

Rich 

******************************************************************
Rich Verjinski    The MITRE Corporation  rich@gateway.mitre.org