I decided to go delving into the logs on my UT box, and found the following interesting message in kern.log: "eth0: too many iterations (6) in nv_nic_irq". There are a bunch of these messages in there, ranging back in time as far as the logs go.
I did some searching online and came across this post, which references a specific issue with nVidia-based NICs and also states that it was fixed in the Debian kernel 3 years ago (roughly kernel 2.6.22 according to that post).
I know that UT 8 is running a much more up to date kernel than that, so I wonder why this issue still remains? It lists a modification to /etc/modprobe.conf, but I am loathe to make modifications, especially since that file doesn't exist in my /etc directory.
Specifics on hardware:
* AMD Athlon 64 3200+ 939 socket
* GeForce 6600
* 2 x 1Gb DDR400
* DFI LANPARTY UT nF4 Ultra-D 939 NVIDIA nForce4 Ultra ATX AMD Motherboard
Untangle is Build: 8.0.0~svn20101110r27850release8.0-1lenny
The motherboard uses a Vitesse VSC8201 for one ethernet port and a Marvell 88E8001 for the second. I have the Vitesse plugged into the external (i.e. cable modem) network and the Marvell is on the internal network.
At any rate, I will at this point open this up to discussion.