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Old 07-17-2006, 06:04 AM   #1
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ip (v4) address taken by electricity?

Electricity went off - ip-address disappeared, dhcp died? Sounds stupid (to me anyway) but seems it's true. An ordinary pc with Fedora Core 5 on it ran smoothly until suddenly the pc went down as the electricity cut off (thunder, broken cable, ..dunno, but the whole house went dark). Next boot worked all right, except no network connection was there - first thought was that ISP just had some problems, but now, some days after, still no network.

I've searched these forums, google, friends, newspapers, trashcans, even under my bed without luck. Most of the problems I read from other people were about not getting dhcp work (but they had ip4 address anyway, for eth0), and I guess I found one post somewhere which seemed to be like mine, but it was older than dinosaurs and lacked a solution..

I checked the network card and cable using a hub and another pc - works fine. The only problem seems to be that ifconfig eth0 shows only ipv6 address, though there should be ipv4 address present too - ifup eth0 doesn't work: dhclient is unable to fetch anything (it just tries and tries and in the end tells me the discovery fails). I've tried resetting all eth0 and ethernet-related (pppoe) configurations, dhcp/dhclient configurations, removed the card, disabled/enabled it in bios, tried Kudzu..nothing seems to work. I've got a laptop connected to the same adsl box this pc is connected to, and the laptop is running perfectly; also, as I said, ethernet works great if I specify a static ip address, but if I try to use dhcp (or ping any ip-address or hostname outside the local ethernet), it fails.

So: how should I proceed? Can I somehow make sure every configuration for ethernet/pppoe is cleared, and then re-try again? Or is there some easier way? And The Question: how on earth can a shutdown caused by a sudden lack of electricity destroy my internet connection settings?

Also, I noticed I don't have any kind of ifcfg-eth0 files anywhere (should there be?)

A million thanks for answers - I've used almost every MacGyver trick around, and still no internet.

Waiting for your tips,


EDIT: which files does ifconfig read to get the information from? What config files does ifup use? What about dhclient? And lastly - can Wake up on LAN have anything to do with this, as one webpage suggested (though it was a bit different kind of problem)? What determines which one I use, ipv4 or ipv6 address? Can ipv6 address somehow scramble ipv4 address?

Last edited by b0uncer; 07-17-2006 at 07:01 AM.
Old 07-17-2006, 07:13 AM   #2
Registered: Apr 2006
Location: Nairobi
Distribution: CentOS
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try this

i think ifcfg-eth0 should b there in /etc/sysconfig/network-scripts/
permissions 644 owner root group root


in ur case BOOTPROTO=dhcp

On startup, dhclient reads the dhclient.conf for configuration instructions.It then gets a list of all the network interfaces that are configured in the current system. For each interface, it attempts to configure the interface using the DHCP protocol.

i guess dhclient wont work coz ifcfg-eth0 is missing.
let me know if this helps
Old 07-17-2006, 11:33 AM   #3
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After all it wasn't dhclient though it seemed so. I'm not completely sure what struck the card, but definitely something was stuck; the thing that saved the situation was simply unplug the whole computer (both power and network cables), like I already had tried, but after that press the power button so the powerbox on the back would discharge all the currents, then re-plug the cords and start the machine. Seems it did the trick..

This far I've thought that the small charge that is left in the computer after unplugging it couldn't actually do such a thing ("remember" something, causing a stuck-situation) but seems it can. I've seen many times how the leds on the front panel blink after the machine is unplugged if one presses the power button, but I'm glad I recalled that now and tried out..

I still don't get why I don't have ifcfg-eth0 there; is it supposed to vanish when no connection is available?

Nevertheless, thanks for ideas


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