Message contains NUL characters ...

David R Bosso dbosso at
Thu Apr 28 16:51:01 EDT 2005

--On Thursday, April 28, 2005 4:13 PM -0400 Joseph Brennan 
<brennan at> wrote:

> --On Thursday, April 28, 2005 16:22 -0300 "Marc G. Fournier"
> <scrappy at> wrote:
>> Someone mentioned that this was, in fact, not forbid'd in the RFCs ...
>> could you point to the relevant RFC where it is?  Considering how
>> 'strict' postfix seems to be, having an RFC to back that up might show
>> some changes over in that camp, at least ...
> RFC 2822, section 4.1, makes null an obsolete character.
> But same, section 2.3, does not explicitly forbid them in bodies.  It
> does say the body must be US-ASCII characters, and following that
> appears to get to section 4.1 defining what characters are.

It's not allowed unless you're talking about the obsolete section as 
mentioned in my previous email.

See the following that defines the syntax:

|    In some of the definitions, there will be nonterminals whose names
|    start with "obs-".  These "obs-" elements refer to tokens defined in
|    the obsolete syntax in section 4.  In all cases, these productions
|    are to be ignored for the purposes of generating legal Internet
|    messages and MUST NOT be used as part of such a message.  However,
|    when interpreting messages, these tokens MUST be honored as part of
|    the legal syntax.  In this sense, section 3 defines a grammar for
|    generation of messages, with "obs-" elements that are to be ignored,
|    while section 4 adds grammar for interpretation of messages.

| text            =       %d1-9 /         ; Characters excluding CR and LF
|                         %d11 /
|                         %d12 /
|                         %d14-127 /
|                         obs-text

| body            =       *(*998text CRLF) *998text

No NUL allowed.

So as before, it's illegal to send them.


David R Bosso <dbosso at|
Systems & Network Manager, Letters and Science IT
UC Santa Barbara - 1054 North Hall 805 451-7160

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