Date: Tue, 11 Apr 95 12:18:32 MDT From: terry@cs.weber.edu (Terry Lambert) To: jc@irbs.com (John Capo) Cc: taob@gate.sinica.edu.tw, freebsd-current@freefall.cdrom.com Subject: Re: Missing telent login prompt Message-ID: <9504111818.AA00822@cs.weber.edu> In-Reply-To: <199504111232.IAA15779@irbs.com> from "John Capo" at Apr 11, 95 08:32:05 am
index | next in thread | previous in thread | raw e-mail
> > > The missing telnet login prompt is timing related. A usleep(250000) > > > anywhere in the child fixes it, at least for 50 login tests. > > > > When I telnet to any of the FreeBSD boxes here, the time it takes > > for the login prompt to show up appears to be more or less random. > > Sometimes it pops up right away, other times it can take up to 6 or 7 > > seconds. Is this the same problem? > > No, the prompt fell on the floor. login is running and waiting > for a user name. Terry says its a option negotiation problem. The reason the prompt is missing is because it was flushed by the client who though it was still option negotiation time. Clearly, a login prompt does not contain IsACommand characters. There are hacks in telnet to deal with BSD 4.2 and BSD 4.3 TCP/IP; basically, the difference between the two is whether or not the out of band data handling works. The telnet and telnetd decide what type they are talking to based on option negotiation order. If the order is of one when it should be of the other, or if a 4.2 implementation is talked to with someone who doesn't use the order of operation hacks and starts using OOB for control messages, then you get "dropped prompt" and other wierd behaviour. This is well known, and is in fact documented in the telnet code that came with Net/2. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.help
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9504111818.AA00822>