Date: Mon, 16 Oct 95 20:50 WET DST From: uhclem%nemesis@fw.ast.com (Frank Durda IV) To: wollman@freefall.freebsd.org, freebsd-bugs@freefall.freebsd.org Subject: Re: bin/771 Additional Message-ID: <m0t51AK-000IthC@nemesis.lonestar.org>
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[0]The problem is caused by a clash between the standard meaning of ISIG [0]mode in the tty driver and the way telnetd(8) implements it using TELNET's [0]LINEMODE TRAPSIG functionality. The fix will be to make telnetd disable [0]all the special characters not implemented by ISIG (and IEXTEN if enabled) [0]when switching into that mode. I noticed another artifact today. Telnet from a 2.0.5 system to a 2.0.5 system. About every other telnet attempt (sometimes only 40% of the time), you don't get a "login:" prompt until you press CTRL-J or CTRL-M AFTER you see the remote system banner. This does not appear to happen on a telnet attempt from 1005 to 1005, but it does happen about 2 or 3 times out of ten on a telnet from 2.0.5 to 1005 or from 1005 to 2.0.5. The two machines involved in this test are identical in terms of computing speed, memory, network card and disk, so these should not be issues. Both systems were completly idle during the tests on a two-node network, so there are no outside traffic. Note that the output of toggle options is 100% identical for the failing and non-failing attempts, so this probably isn't a negotiation problem, or if it is it is a timing problem. Here is the output seen with notations: (Long lines have been folded) >From 2.0.5 to 2.0.5 run as non-root used from console screen F4. % telnet | tee /dev/tty > x1 telnet> Will show option processing. telnet> Trying a.b.c.d... Connected to nemesis.lonestar.org. Escape character is '^]'. SENT DO SUPPRESS GO AHEAD SENT WILL TERMINAL TYPE SENT WILL NAWS SENT WILL TSPEED SENT WILL LFLOW SENT WILL LINEMODE SENT WILL NEW-ENVIRON SENT DO STATUS RCVD DO TERMINAL TYPE RCVD DO TSPEED RCVD DO XDISPLOC SENT WONT XDISPLOC RCVD DO NEW-ENVIRON RCVD DO OLD-ENVIRON SENT WONT OLD-ENVIRON RCVD WILL SUPPRESS GO AHEAD RCVD DO NAWS SENT IAC SB NAWS 0 80 (80) 0 25 (25) RCVD DO LFLOW RCVD DO LINEMODE SENT IAC SB LINEMODE SLC SYNCH DEFAULT 0; IP VARIABLE|FLUSHIN|FLUSHOUT 3; AO VARIABLE 15; AYT NOSUPPORT 255; ABORT VARIABLE|FLUSHIN|FLUSHOUT 28; EOF VARIABLE 4; SUSP VARIABLE|FLUSHIN 26; EC VARIABLE 8; EL VARIABLE 21; EW VARIABLE 23; RP VARIABLE 18; LNEXT VARIABLE 22; XON VARIABLE 17; XOFF VARIABLE 19; FORW1 NOSUPPORT 255; FORW2 NOSUPPORT 255; SENT DO SUPPRESS GO AHEAD RCVD IAC SB LINEMODE MODE EDIT|TRAPSIG SENT IAC SB LINEMODE MODE EDIT|TRAPSIG|ACK RCVD WILL STATUS RCVD IAC SB TERMINAL-SPEED SEND SENT IAC SB TERMINAL-SPEED IS -1,-1 RCVD IAC SB NEW-ENVIRON SEND SENT IAC SB NEW-ENVIRON IS RCVD IAC SB TERMINAL-TYPE SEND SENT IAC SB TERMINAL-TYPE IS "CONS25" RCVD DO ECHO SENT WONT ECHO RCVD WILL ECHO SENT DO ECHO RCVD DO BINARY SENT WILL BINARY RCVD IAC SB TOGGLE-FLOW-CONTROL RESTART-ANY RCVD WONT ECHO SENT DONT ECHO RCVD IAC SB LINEMODE SLC SYNCH NOSUPPORT 0; EC VARIABLE|ACK 8; SENT IAC SB LINEMODE SLC SYNCH NOSUPPORT|ACK 0; FreeBSD (nemesis.lonestar.org) (ttyp0) Here the system waits, NOT displaying the login prompt. System is IDLE. After 30 seconds or so I eventually type CTRL-J or CTRL-M, and then it displays: login: Then I send the CTRL-D. SENT IAC EOF If it doesn't fail, immediately repeat the above steps, with or without the "tee". "Tee" has no effect on the occurrence of the problem. The choice of console screens also has no effect. *End of log* Frank Durda IV <uhclem@nemesis.lonestar.org>|"The Knights who say "LETNi" or uhclem%nemesis@fw.ast.com (Fastest Route)| demand... A SEGMENT REGISTER!!!" ...letni!rwsys!nemesis!uhclem |"A what?" ...decvax!fw.ast.com!nemesis!uhclem |"LETNi! LETNi! LETNi!" - 1983
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