TOPS-20 Telnet and Port Forwading issue

[Eric Smith]

It's the SGA (suppress go-ahead) negotiation that's necessary to avoid line
mode.

Many telnet clients don't try to negotiate any telnet options if you
connect to a non-standard port, because they assume that you're talking to
something other than a telnet server, and that you therefore want an 8-bit
transparent connection with local line editing. Examples would be to telnet
to an SMTP server, FTP server, etc. for testing purposes.

A telnet client that has that behavior but no provision for overriding it
is defective, and should either be fixed, if possible, or deleted with
prejudice.