Network/Internet Connection Lost after Dual Boot Rebuild

Network/Internet Connection Lost after Dual Boot Rebuild

by Red Morris -
Number of replies: 6

OK, this one has me a little stumped. I have a box for playing about with and learning Moodle, and it's been rebuilt at least 7 times in the last 4 weeks. Mostly using SuSE, once using Windows Server 2003 and once with both. Not once during those did I have this problem.

Yesterday I zapped the box and partitioned 15Gb for Windows, 55Gb for a common Data share, and left 15Gb unpartitioned . I installed Windows Server 2003 on the first partition from a Ghost partition image, and installed SuSE on the unpartitioned space and left it going last night.

I finished it off today and now Linux will not connect to the internet or network, but Windows works fine. I've quadruple checked the DNS and Gateway settings, tried pinging the DNS servers by their IP address, swore at it, disabled the firewall, all to no avail.

It's baffling me quite frankly

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In reply to Red Morris

Re: Network/Internet Connection Lost after Dual Boot Rebuild

by Henry Johnson -
Hi Red,

Not much to go on. Does the box have more than one network interface?

I assume you've run ifconfig -a, looked at the /proc/net directrory (don't know what any of it means, but it looks cool!). I did a dual linux install (same OS) and the network interfaces were named in a different order. Not obvious reason. Even more fun to be had when you do a Solaris upgrade and it decides to reorder your disk device names.

I know Windows likes to overwrite the boot blocks on disks, so your install proceedure looks fine. Don't use SUSE, so I am not sure how it does its hardware recognition thing. Maybe a module hasn't loaded into the kernel.

Does your local loopback interface work? Maybe Windoze zapped some setting in your networking hardware.

So, ifconfig -a, netstat -r (or -a or something like that), output looks fine and the little green light thingy on the card lights up with the cable in it? Again, if you have more than one interface, plug the cable into the other hole and see what happens.

dmesg and the boot sequence recognise the network card and don't spit out any errors?

Err. Hate to flippant, but we fixed my father-in-law's AMD laptop by ditching the 64 bit SUSE (which he paid for) and installing Ubuntu. Ubuntu seem to do the best job at getting networking right first time in initial installs.

Funny. When I have multi-boot networking problems, its the other way round! With the before mentioned laptop, wireless was unstable (some XP SP 2 bug according to Microsoft), but fine under Ubuntu.

Cheers and good luck!

Henry
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In reply to Red Morris

Re: Network/Internet Connection Lost after Dual Boot Rebuild

by Visvanath Ratnaweera -
Picture of Particularly helpful Moodlers Picture of Translators
Obviously this is only remotely connected to Moodle.

Anyways you should have known that GPL'd software (and the people behind them) react violently in the vicinity of greedy licences. The whole LAMP stack including Moodle is deeply upset and won't say a word until you delete those offending partitions! smile

Seriously, the two network card theory is a good one.

What does "ifconfig -a" has to say.

How about "ifconfig INTERFACE"?

Does your network card have LEDs. Does the green one light connecting to the hub? Does the yellow one blink, during boot-up (assuming DHCP)?

Can you ping within the LAN?

What is the output of "route -n"?

Once all these tests pass, listen to "tcpdump -i INTERFACE" for a while.
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In reply to Visvanath Ratnaweera

Re: Network/Internet Connection Lost after Dual Boot Rebuild

by Red Morris -

A bit more info for you.

The cable is plugged in (I know you were thinking it ;o) ), there's only one network card, the network does have a proxy server, the light is on on the card.

I tried the suggested commands and this is what I got

ifconfig -a : IP and Gateway were OK. eth0 RX had 270 overruns. All other values of errors, overruns, etc in eth0 and lo were 0, except the packets sent.

ifconfig INTERFACE returned "INTERFACE: error finding interface information: Device not found

route -n all the info looked ok.

What stumps me is that this has all worked several times before with no physical changes to the machine. I'm starting to wonder if it's time to just reinstall SuSE and hope

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In reply to Red Morris

Re: Network/Internet Connection Lost after Dual Boot Rebuild

by Visvanath Ratnaweera -
Picture of Particularly helpful Moodlers Picture of Translators
> ifconfig INTERFACE returned "INTERFACE: error finding interface information: Device not found

INTERFACE (in uppercase) was supposed to be a place holder for your actual interface. In your case "ifconfig eth0" as root. Which you seem to have done already:

> IP and Gateway were OK. eth0 RX had 270 overruns. All other values of errors, overruns, etc in eth0 and lo were 0, except the packets sent.

There should NOT be so much overruns. This could be a half duplex/full duplex/negotiated conflict. I can remember, in certain combinations of the switch and network card, you shouldn't force any duplex mode rather allow it to negotiate.

> I'm starting to wonder if it's time to just reinstall SuSE and hope

You must be joking!

In IT there is no place for hope, Murphy took them all sad
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In reply to Visvanath Ratnaweera

Re: Network/Internet Connection Lost after Dual Boot Rebuild

by Red Morris -

>INTERFACE (in uppercase) was supposed to be a place holder for your actual interface

Well I guess my cover as a Linux guru is blown then! Yes, I am a noob! smile

>This could be a half duplex/full duplex/negotiated conflict

Ah! Ooo! Ah! I did change the network card to full duplex under windows. I would have thought that's merely a driver adjustment, but it's worth changing it to see.....after I get back from this one day course on nothing. angry

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In reply to Red Morris

Re: Network/Internet Connection Lost after Dual Boot Rebuild

by Henry Johnson -
Ahh, duplex issues.

When I had a real job, we had a nifty Fluke network tester (was about $1000 US, size of a tricorder), and had lots of fun solving duplex mismatches between switches, networking cards and anything else that would spit out a network packet. I think tools such as tcpdump and ethereal (its got pretty GUI and I think it will run under Windoze) can give you the same info if you know where to look.
 
Back in the old days, auto neg was dodgey and you usually had to "force" everything to full duplex if you were after performance. So I guess the next question is how to set the duplex of a card under SUSE. I think ifconfig can do it. But it can be driver specific.

Cheers
Henry
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