Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!samsung!umich!sharkey!ionic!gm From: gm@ionic.UUCP (Greg Miller) Newsgroups: comp.protocols.tcp-ip Subject: Telnet's ECHO option Message-ID: Date: 21 Nov 90 20:19:26 GMT Lines: 38 I'm in the midst of writing my own tcp/ip implementation, and have been caught up with what seems to be a problem - determining who exactly does any echoing in a telnet session. I've read the RFC covering the telnet ECHO option (RFC 857), and thought that I understood it. This explanation is an oversimplification, but shows the way I interpreted it: (There's no need to explain the need to respond to a "WILL/WONT" with a "DO/DONT" rather than the other-way-around; I'm fully aware of that, and make use of it. I don't include it here for simplification.) (1) If I send a DO ECHO and receive a WILL ECHO, I expect the host to echo each character I send to them. (2) If I send a DON'T ECHO and receive a WON'T ECHO, I expect NOT to receive an echo for each character sent. Part (1) above seems to fit properly. If I send the DO ECHO, the host happily echos everything back to me. However, part (2) doesn't seems to always apply - On varied pieces of equipment, it does what I expect - a DONT/WONT pair causes the host not to echo anything back. However, whenever I try this when I'm connected to a BSD machine, the host accepts my DONT ECHO, replies with WONT ECHO, and then procedes to continue echoing anyways. What gives? Am I interpreting things wrong? Is this option incorrectly implemented in some BSD revisions? -- +----------------------------------------------------------------+ | A sign of mismanagement, over- | Greg Miller | | complication and overall idiocy: | ..ames!sharkey!ionic!gm | | | gm@ionic.uucp | | "Designed By Committee" | | +----------------------------------------------------------------+