Ftp-WG: Re: MLST draft - NUL CR LF again

"Gregory A Lundberg" <[email protected]> Wed, 24 Apr 2002 22:34:33 -0500

Newsgroups	gmane.ietf.ftpext
Message-ID	<[email protected]>

> I thought Telnet by design Can exchange lines of
> completely arbitrary content and length?  Yes CR LF
> ends a line.  To send a line with CR inside, to escape
> the CR, send CR NUL instead.  Always on receipt of CR
> NUL, substitute CR.
>
> This is unambiguous on paper ... no?
>
> For example, we could send the six byte command "STOR
> \r" as the nine bytes "STOR \r\0\r\n" to create a file
> named by the one byte string containing only x0D CR.

RFC 1123 *REQUIRES* the TELNET implementation to accept CR NUL as equivalent
to CR LF.  The the proper intepretation of your example is:

  STOR <SP> <CRLF>
  <CRLF>

And a conforming server SHOULD issue the replies

  501 Syntax error in parameters or arguments
  500 Syntax error, unrecognizable command

in response to the sequence.