Computer sending data while turned off

Question

I have a some what strange problem (which could have an easy and obvious solution for all I know).

My problem is that when I've booted ubuntu (now 10.4 but same problem with 9.10) and turns it off it starts sending a HUGE amount of data via the ethernet cable, so much in fact that my router can't handle it and stops responding.

As far as I can tell the computer is completely turned off with no fans spinning. I can add that if I boot windows I do not have this problem, just when exiting ubuntu.

There are two "fixes" for my problem:

• Pull the ethernet cable until the next boot
• Turn off power to the PSU and wait for the capacitors to unload

Is there anyone who knows what could be going on? I'd be happy to post some logs or conf-files.

Currently I'm using the ethernet port on my motherboard which is a Asus P6T Deluxe V2 with an updated version of the BIOS (maybe not the latest but since it only happens when I've been in ubuntu I don't wanna mess with the BIOS too much).

Regards Nicklas

---------Update 1----------

The router is a D-Link DIR 655 with the latest firmware.

---------Update 2----------

I've now reinstalled ubuntu (with 10.4) and I still experience the same problem.

---------Update 3----------

Well I still haven't found a solution to this problem :(

Answer 1

I opened a topic in Ubuntu forums, and with their help, I made an workaround, that is working nicely so far. Check Topic here: http://ubuntuforums.org/showthread.php?p=9617739

Answer 2

What is indicating that your Ubuntu-shutting-down computer is sending data to your router?
I mean, do you have any other things to show that there was data being sent?
(for example, you might put a hub in the path and capture data on it while the shutdown is in progress... does that show such transfers?)

A simpler reason could be a driver malfunction causing the router to crash/stall.

Towards that end, it might help to publish your router specs too.

---

Update on your comment:

• I am a little surprised with your problem. Do you by any-chance have a Wake-up-on-LAN configuration enabled in your PC-BIOS?

• If you want to capture data between the router and the PC you will need another piece of hardware called a Hub which lets you 'tap' the wire between the PC and the Router (3 ethernet wires: 1 from PC, 1 from Router and a 3rd to a different PC capturing packets). Alternatively, if your router has more Ethernet ports and supports 'port-mirroring' you can pickup captures with that setup.

Answer 3

Here are my troubleshooting steps:

• Plug a network cable from the router and into my laptop and run Wireshark and see packets its sending out
• Try a different router. No offense, many residential routers suck and/or are buggy (and they do this on purpose...but we won't discuss those semantics here ;))
• Perhaps try plugging into a dumb switch w/o the router and see if there is activity, if there is then there is something wrong with your computer - if not its the router
• If there is no activity in the dumb switch after powering down, then plug in the router to see if it makes your computer go crazy. If not, then I would say that port in the router is bad
• Try another ethernet port in the router, on my Linksys WRT54GL, one of the ports actually went bad and makes my DSL modem go crazy
• Buy a ethernet card and see if the problem persists

Answer 4

It could be a faulty Ethernet cable that sends out noise as the signal is coming down. Try a different cable.

Answer 5

I have the EXACT SAME PROBLEM! In fact, I just discovered it because my router freezes.

I tried capturing with wireshark and tcpdump, directly connecting two computers. The other ethernet shows that it's receiving constant 192k but they capture nothing (must be faulty packets)

The only workaround so far is turning off PSU and turning it again.