I'm no expert, but dmesg says that vr0 is your via-rhine network card.
There's no mention of dc0 which is your other network card, so I'd guess
that your vr0 card is either dying, slightly non-standard, or something else
is wrong with it.

Its probably not a cabling issue or a hub/switch problem.

-----Original Message-----
From: Roberto Pereyra [mailto:rjpereyra at gualeguaychu dot gov dot ar] 
Sent: Sunday, 19 September 2004 11:53 a.m.
To: m0n0wall at lists dot m0n0 dot ch
Subject: [m0n0wall] m0n0wall mbufs exhausted

Sep 18 16:50:58 villa /kernel: dc0: <Davicom DM9102A 10/100BaseTX> port
0xec00-0xecff mem 0xdfffff00-0xdfffffff irq 11 at device 8.0 on pci0
Sep 18 16:50:58 villa /kernel: vr0: <VIA VT6105 Rhine III 10/100BaseTX> port
0xe800-0xe8ff 
...
Sep 18 16:52:54 villa /kernel: All mbufs exhausted, please see tuning(7).
Sep 18 16:52:54 villa /kernel: vr0: no memory for tx list
Sep 18 16:52:54 villa /kernel: All mbufs exhausted, please see tuning(7).
Sep 18 16:52:58 villa last message repeated 4 times
Sep 18 16:52:58 villa /kernel: vr0: watchdog timeout
Sep 18 16:52:58 villa /kernel: All mbufs exhausted, please see tuning(7).
Sep 18 16:53:29 villa last message repeated 31 times
Sep 18 16:55:29 villa last message repeated 120 times
Sep 18 16:58:39 villa last message repeated 32 times
Sep 18 16:58:39 villa /kernel: vr0: no memory for tx list
Sep 18 16:58:39 villa /kernel: All mbufs exhausted, please see tuning(7).
Sep 18 16:58:43 villa last message repeated 4 times
Sep 18 16:58:43 villa /kernel: vr0: watchdog timeout
Sep 18 16:58:43 villa /kernel: All mbufs exhausted, please see tuning(7).
Sep 18 16:59:14 villa last message repeated 31 times
Sep 18 17:01:00 villa last message repeated 106 times
Sep 18 17:04:45 villa /kernel: All mbufs exhausted, please see tuning(7).
Sep 18 17:04:45 villa /kernel: vr0: no memory for tx list
Sep 18 17:04:45 villa /kernel: All mbufs exhausted, please see tuning(7).
Sep 18 17:05:16 villa last message repeated 31 times
...