Imagine a network with four machines and a 10/100 switch.

Two of the machines are NetBSD, and two are Windows.

All have DFE-530TX cards.

The NetBSD machines can't seem to keep their cards configured properly in
relation to the switch.  Sometimes transfers are horribly slow!  Often,
unplugging a cable from the switch and plugging it back in causes the
negotiation to happen properly and the nextwork will go fast again.
Power-cycling the switch will also solve the problem, until one of the
NetBSD machines is rebooted.

The Windows machines seem to have no problems with the DFE-530TX cards,
which leads me to believe something is odd with the NetBSD drivers.

vr0 at pci0 dev 9 function 0: VIA VT3043 (Rhine) 10/100 Ethernet
vr0: interrupting at irq 12
vr0: Ethernet address: 00:80:c8:f8:f2:d3
ukphy0 at vr0 phy 8: Generic IEEE 802.3u media interface
ukphy0: Am79C873 10/100 media interface (OUI 0x00606e, model 0x0000), rev. 0
ukphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
 -snip-
vr0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
address: 00:80:c8:f8:f2:d3
media: Ethernet autoselect (100baseTX full-duplex)
status: active
inet 192.168.1.1 netmask 0xffffff00 broadcast 192.168.1.255

-- 
Dan J. Fraser <dfraser@capybara.org>
PGP: 0xF3972A01 (17 B7 24 90 27 05 B8 92  4F 7F 61 18 B9 D1 17 CE)
"People who read Wired are *exactly* everything that's wrong with the net."