Summary, RE: Request for Help With TCP/IP

[Charles Hedrick]

>The basic point was that the telnetd is not totally transparent, i.e.
>it expunges 0xff bytes.  There are a number of ways around this

Telnet is a protocol.  It allows transparent connections.  It sounds
like your problem is that you're trying to talk with telnetd without
following the telnet protocol.  0xff is used by telnet as an escape.
That is 0xff followed by another character is a special function.  But
0xff 0xff turns into a real 0xff.  Thus you can send any character
over a telnet connection.  We successfully do both UUCP and xmodem
over telnet.  However with our cisco terminal servers, the user has to
issue a command "term download" in order to get CR handling that is
completely transparent.  As I recall, here's what you have to do
in order to get transparent behavior with telnet:

  when sending:
    0377 --> 0377 0377
    015 --> 015 000
  when receiving
    0377 0377 --> 0377
    0377 other things: see the telnet spec.  You may be able to
	get away with ignoring them, but you're really supposed
	to respond to these special codes.  If you want to try
	ignoring them, you're likely to have to skip 2 bytes
	after that 0377.
    015 000 -> 015
    015 012 -> depends upon your telnetd.  Probably can stay 015 012,
	but you should check.  Could need to get turned into bare 012.

Note that Berkeley UUCP already supports telnet over TCP connections,
so you really should ask your vendor to support uucpd.  If you're
going to do your own, try to use the same protocol on the same port
number (but do pick a different port number if you're not sure you are
compatible).