Date: Tue, 19 Dec 1995 04:05:40 -0700 (MST) From: Ade Barkah <mbarkah@hemi.com> To: hackers@freebsd.org Subject: Help with telnet, flow control, and IXON. Message-ID: <199512191105.EAA02661@hemi.com>
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Hello, [Background] We have users logging into a FreeBSD 2.0.5-R machine by modem via a terminal server. Users connect from the terminal server to the FreeBSD box via `telnet', with the escape character supressed so they can transfer files (this all works fine.) [Problem] Users running certain applications on the FreeBSD box sometimes get garbled output. To be exact, the garbled output occurs soon after an application turns off IXON in the terminal's c_iflag. The user gets a string of garbled output, then everything fixes itself. Note, if a user telnets to the FreeBSD box via an intermediate site, the garbling disappears. It also never garbles when the user is running under `script'. [Question] My temporary fix is to recompile programs like telnet, etc., making sure IXON is left alone. I'm wondering what the "real" solution is. Another thing I can't resolve in my mind: the above shows that there's software flowcontrol going on between the terminal server and the FreeBSD box. But then, why do programs like `sz' work ? Is sz smart enough to escape and switch the START and STOP flow control characters ? And if I do let applications disable IXON, what other method of flow control can be put in place ? Hardware signaling is obviously out of the question over tcp/ip. I wonder why tcp/ip's own flow control algorithm doesn't work here. Thanks in advance for any hints... it's 4am and I'm pretty confused. =-) -Ade -------------------------------------------------------------------- Inet: mbarkah@hemi.com - HEMISPHERE ONLINE - www: <http://hemi.com/>; --------------------------------------------------------------------
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