Bug 29577

FreeBSD 4.3-STABLE freezes intermittently when using Linksys EtherFast LNE100TX NICs.

I have confirmed this using two completely different servers (an eMachine 533i and a Compaq Presario, both built from the ground up with a clean install of FreeBSD 4.3-STABLE.

Both servers were tested with two different (but identical) Linksys cards, one a year old and fully proven under many months of FreeBSD 4.1 traffic, and the other brand new and out of the box.  The problem disappeared immediately as soon as a Netgear FA310-TX card was substituted.

The crash is triggered by a large burst of outbound IP traffic; ie, a remote rsync of /usr/home (50MB+), a large (10MB) scp download by a remote host, even a large email message downloaded via IMAP (1.5MB).

When the crash occurs, the host goes into complete freeze -- locked keyboard (unable to ALT-F* through consoles or toggle scrl-lock).  Only known remedy is hardware boot.

The most complex part of the problem is that the problem is seemingly sensitive to the "network environment" -- ie, whatever else is happening on the local segment, and possibly the data throughput rate provided by the local gateway.

In my case, the problem was repeatedly reproducible, on either server, at my local ISP/colo vendor (AO.net), yet could not be reproduced on my home network (with either server).

The only environmental difference I can attribute this to is that, at the colo facility, there were about 20 other hosts on the same segment, broadcasting god-knows-what through my NIC, and the data transfer rate was limited to about 30kbps.  At home, I had only a few other local computers on the same segment (mostly quiet), and I was able to download huge amounts of data from the same servers at a very high speed.

I don't know if this gives you enough information to attempt a fix, but I'm telling you all that I know.  Feel free to contact me if you desire additional details.

Fix: 

Replace Linksys with Netgear FA310-TX
How-To-Repeat: Intermittent, possibly dependent on surrounding network environment.  See description.