Thread View: comp.protocols.appletalk
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Started by Jim Gogan
Tue, 15 Dec 1992 19:30
NCSA Telnet/MacTCP/Mac LC
Author: Jim Gogan
Date: Tue, 15 Dec 1992 19:30
Date: Tue, 15 Dec 1992 19:30
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We have been experiencing an on-going problem that, now that the semester is winding down, we're trying to push to find an answer to. Basically, we have found that it is very easy (just by typing real fast, for example) to lock up an LC running telnet sessions (doesn't matter to which hosts) with: - NCSA Telnet (either version 2.3 or 2.5) AND - MacTCP (version 1.1) Doesn't matter what brand of Ethernet adapter in the Mac; doesn't matter whether I'm running System 6 or 7. We do NOT have this problem running SU/Mac and MacTCP, nor do we have this problem running NCSA ver 2.5 with hardware=ether. Has anyone else seen this? One interesting point that may be relevant. I connected our lil'ol'Lanalyzer, filtering for packets to-from the Mac LC I was working on. And noticed the following: - when using NCSA Telnet with hardware=ether, the TCP Window size used by the Mac is whatever I specify with the rwin= parameter in config.tel (no surprise there); I used values from 512 to 4096 -- all was OK; - when using SU/Mac IP with MacTCP, the TCP Window size used by the Mac is 1336; - HOWEVER, when using NCSA Telnet with MacTCP, the TCP Window size supposedly used by the Mac (as shown in the packet trace) is 4788; that just seems kinda odd to me. Of course, the rwin parameter in config.tel has no effect if you're using MacTCP. Any liklihood that this is related to our problem, and, if so, is there any way to change parameters like this for MacTCP (or is it up to the application to deal with that)? Pointers will be - as always - greatly appreciated. Please respond to me directly thru e-mail. I'll post the appropriate response (if any). Thanks! -- Jim Gogan (Jim_Gogan@unc.edu) OIT Networking Systems University of North Carolina at Chapel Hill
Re: NCSA Telnet/MacTCP/Mac LC
Author: Roy Smith
Date: Tue, 15 Dec 1992 22:45
Date: Tue, 15 Dec 1992 22:45
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gogan@hermes.oit.unc.edu (Jim Gogan) writes: HOWEVER, when using NCSA Telnet > with MacTCP, the TCP Window size supposedly used by the Mac (as shown in > the packet trace) is 4788; that just seems kinda odd to me. Of course, > the rwin parameter in config.tel has no effect if you're using MacTCP. I wonder if this is in any way related to the extremely slow performance we get with Telnet. We run NCSA Telnet 2.4 and 2.5 on Mac-IIci's running 7.0.1 w/ MaTCP 1.1 or 1.1.1 on a relatively lightly loaded thin ether segment. Telnetting to an otherwise idle Ultrix box sitting right next to my Mac, I get performance (for big blocks of text, full screen updates in a 40-line window) that seems to me to be about on a par with a 9600 bps connection. Currently, I'm at home running kermit (also with a 40-line screen size) over a 19.2 V.32bis connection to a terminal server telnetting to that same Ultrix box through GOK how many bridges, repeaters, etc and getting performance which is about as good. -- Roy Smith <roy@nyu.edu> Hippocrates Project, Department of Microbiology, Coles 202 NYU School of Medicine, 550 First Avenue, New York, NY 10016 "This never happened to Bart Simpson."
Re: NCSA Telnet/MacTCP/Mac LC
Author: Matt Healy
Date: Wed, 16 Dec 1992 18:15
Date: Wed, 16 Dec 1992 18:15
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In article <1gln72INN8la@calvin.NYU.EDU>, roy@mchip00.med.nyu.edu (Roy Smith) wrote: > > gogan@hermes.oit.unc.edu (Jim Gogan) writes: HOWEVER, when using NCSA Telnet > > with MacTCP, the TCP Window size supposedly used by the Mac (as shown in > > the packet trace) is 4788; that just seems kinda odd to me. Of course, > > the rwin parameter in config.tel has no effect if you're using MacTCP. > > I wonder if this is in any way related to the extremely slow > performance we get with Telnet. We run NCSA Telnet 2.4 and 2.5 on And I wonder if this is related to the intermittant problems I have with Telnet. Sometimes we have a pair of machines that cannot talk to one another via telnet; either machine can ping the other so I *know* they have a working physical connection, and either machine can operate via telnet with *every other machine* (here or thousands of miles away) that I try. The problem seems to be related to initial protocol negotiation. What's even stranger is that if I am trying to open a Telnet session and it's not working, I can open a second ftp session to the same host. Not only does the ftp connection work *fine*, but once it starts the problem with the telnet session suddenly goes away by magic!?!? The host involved is a Silicon Graphics workstation running Irix 4.0.1 System V; the clients are Macs running NCSA Telnet and MacTCP 1.1 (I know there's a newer version out, but thanks to Apple's ridiculous new license policies we *cannot* afford it). Matt Healy "I pretend to be a network administrator; the lab net pretends to work" matt@wardsgi.med.yale.edu
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