*BSD News Article 56948


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From: jdp@polstra.com (John Polstra)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: FreeBSD crashes TCP/IP printer
Date: 13 Dec 1995 12:42:50 -0800
Organization: Polstra & Co., Seattle, WA
Lines: 47
Message-ID: <4andsa$l3@austin.polstra.com>
NNTP-Posting-Host: austin.polstra.com

Please, if you have any idea how to track down the cause of this
problem, let me know!

Something _very_ strange is going on between my two FreeBSD machines
and my network printer.  Merely connecting to the printer from a
FreeBSD machine crashes the printer.  Connecting to the printer in
exactly the same way from either of two other machines works fine.

The printer is a Lexmark 4039, with an Ethernet card that supports
TCP/IP.  The printer's network interface supports several ways of
sending jobs to the printer.  One method is to simply FTP the file
to the printer.  I've been using it in that way for almost 2 years
from a system running SVR4, and it works fine.  (I have spooler
software that does the FTP transfer.)

But, if I try to FTP to the printer from a machine running FreeBSD,
the printer immediately dies.  The "ftp" command on the FreeBSD
side just hangs, and "netstat" shows that the connection is sitting
in the SYN_SENT state.  From that point on, the printer is dead.
I have to power-cycle it to get it working again.

FTPs from my SVR4 machine and from my router (Telebit NetBlazer)
to the printer work OK.  But FTPs from either of my two FreeBSD
machines kill the printer.

One FreeBSD machine is running 2.1.0-951026-SNAP, and has a SMC
EtherPower card.  The other FreeBSD machine is running 2.0.5-RELEASE,
and has a SMC 8013 Ethernet card.  The working SVR4 machine also
has a SMC 8013.

Note, this has nothing to do with FTP itself.  Merely trying to
connect via TCP/IP from a FreeBSD machine to the printer causes it
to crash.  That is clear from the fact that the connection hangs
up in the SYN_SENT state.  (But, I confirmed it with a tiny Python
program.)  Because the printer crash happens at the _earliest_
stage of TCP/IP connection establishment, I'm inclined to think
that the problem is at the Ethernet layer.

Another clue:  If I FTP to the printer from a _remote_ FreeBSD machine,
(so that the connection comes in through my router), it works fine.

Any ideas on how to diagnose this problem?  I want to replace the
SVR4 machine with FreeBSD, but I need to be able to print.
-- 
   John Polstra                                       jdp@polstra.com
   John D. Polstra & Co., Inc.                Seattle, Washington USA
   "Self-knowledge is always bad news."                 -- John Barth