Re: telnet v.s. rlogin

Charles Hedrick (
Thu, 27 Oct 88 14:59:22 EDT

I certainly don't read the telnet spec's as requiring any kind of line
structure (aside from the GA stuff, which based on recent
correspondence is now officially dead). As far as I can tell, end of
line is treated specially because the protocol designers thought that
some host might have line structure, and might need to make a
distinction between CR and EOL. However as far as I know few if any
systems actually make this distinction. (Many systems represent end
of line in files in different ways, but that's not the issue. The
issue is whether what comes from the terminal when the user wants to
generate an end of line is CR.) Thus I suspect this distinction is
about to become defunct, as GA apparently has. The host requirements
draft implies that CR LF and CR NUL are to be treate the same, and are
to have the effect of the user typing CR. In that case the special
role of CR more or less vanishes. CR just gets translated to CR LF or
CR NUL and back again as a historical artifact. It becomes a concern
only to implementors, like IAC doubling. I hadn't noticed the RFC for
a negotiation to control whether CR is sent as CR LF or CR NUL.
However on a system where CR is end of line, CR LF and CR NUL are
going to be treated the same, and it is hard to see why the telnet
server would care which one is used. So I don't see any reason for
the server to implement this option. The user end would only be done
if it turned out that some other system actually needed it.

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