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I'm having a problem where my Ubuntu Server random stops working. I can't access my websites, can't get my email, can't login via SSH, etc. I've got two theories: one is that Ubuntu has some kind of power setting that shuts down Internet after x hours of inactivity or something, the other is that my router is being stupid.

Are there any power or Internet settings in Ubuntu that I should look at (through command line; no GUI installed)?

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There are no settings in the server edition that would cause this from the ubuntu side. What happens when you open up a console on the machine? (i.e. plug in a monitor and keyboard). It sounds like a hardware error to me ... could be anything from bad ram to a nic that isn't being handled correctly. Can you place another device on the router and see if it has similar access problems? (To eliminate the router)

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I believe it may be a hardware failure. I've commenting with "Patrick R" on his post and he mentioned the same thing. It's probably not the router, since three other computers are connected to it and do not experience this problem. As far as what the console displays when this happens, here's a screenshot: ... keyboard does nothing, even ctrl-alt-del doesn't work (it normally restarts the server). – grant Aug 11 '10 at 4:33
yup deffinantly a hardware problem that is causing the server to lock up. Good luck chasing it down. – trent Aug 11 '10 at 14:57

There may also be the possibility of the power management features of your BIOS as well as inactivity timer/timing from your ISP/router (if you are running into this remotely too).

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I don't think it's a power setting (you've installed a server, right?) or your router.

I'm going way, way out on a limb here and going to give an educated guess (since I don't have much to go on). Might you be losing your static ip to a dhcp lease from a basic server install? This can happen even though you probably went through the trouble to assign a static IP.

Check to see that you don't have dhcp3-client assigning a dynamic IP at random moments to your NIC. You'll see it in your logs if so. Do an apt-get remove dhcp3-client if so.

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The problem doesn't have anything to do with my ISP; when this happens, I'm unable to connect to it DIRECTLY (via 192.168.1.x). – grant Aug 9 '10 at 3:15
I'm guessing that you're correct. I don't think it's your ISP either. Did you recently build this server or has it been online for a while? ( I know my suggestion above sounds crazy - helped out someone else who gave almost exact same description as you.) – Patrick R Aug 9 '10 at 13:37
I set up the server in April. It just did it again by the way, so before I restarted it I plugged in a monitor and keyboard to see what was going on. What I found was that the server seemed to be locked up. There was no spot to login, the keyboard didn't do anything, and a saw a screen full of... I don't know. I took a picture; hopefully you can make heads or tails of this: – grant Aug 9 '10 at 17:31
typo: and I saw a screen – grant Aug 9 '10 at 17:33
looks like your Linux kernel is either not compatible with your hardware (hard to believe since it originally worked) or you actually have hardware failure. Can you swap out your NIC (since that seemed to be the original culprit. At this point I am only giving you troubleshooting steps (not specific answers). You might want to create another question and bring some kernel experts into the mix if you think all of your hardware is good. – Patrick R Aug 9 '10 at 19:18

Run a traceroute off the Ubuntu server when you see the outage. This will show you which connection is actually failing. I'm guessing that it's probably an ISP outage or, if you're using a consumer grade router, the router its self. Don't forget to check cables.

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The problem doesn't have anything to do with my ISP; when this happens, I'm unable to connect to it DIRECTLY (via 192.168.1.x). – grant Aug 9 '10 at 3:15

Check if you have IPv6 enabled, I had the same problems and disabling IPv6 fixed them

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Do you have a backup server ? If yes, it would be good to make sometests like memtest, and connect back-to-back the server's machine with something else, let's say a laptop and see the results. You could also test the hard disks.

Also, what kernel do you have ? 2.6.28 ? When was your last update ?

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