Network Communications Problem

[Chris1701]

I've got a really tough problem that so far has defied diagnosis and I'm hoping for a suggestion or two.

Here's the setup: Verizon DSL with a Linksys BEFSR81 router. Two computers, one with Windows 2000 and one with XP Pro.

The problem is that at some point several weeks ago the XP machine lost it's ability to communicate with the internet. All the while the Windows 2000 machine continues to work fine.

So far I've scanned the XP system with NOD32, Spybot and ComboFix and didn't find anything wrong. After testing the cable (I have a Microtest Ethernet cable tester) which was fine and seeing that I'm getting link and activity lights on both the NIC and router I figured maybe the integrated NIC was bad. Also when I check the status of the local area connection I see packets sent but no packets received.

I took the XP system home and when I hooked it up to my Linksys WRT54G router TCP/IP communication worked fine with no problems.

When I took the system back to the office and hooked it back up I had the exact same problem. I tried switching ports, putting the cable for the Win2K system into the XP port and visa versa but still the exact same problem: The Win2K system continued to work while the XP system continued to not work.

The problem is that the XP system seems to simply not be able to receive data from the router. The windows DHCP client can't get an address and if I manually set the IP address, subnet, router and DNS it still can't communicate.

I've checked the router setup and there is no filter or MAC address blocks that would keep the router from sending data back to the XP machine and there was a firmware update which I flashed to the router (from the Win2K machine) and still no go.

Obviously the next step is to replace the router which is not a real expensive proposition but still I hate throwing away what is a perfectly good router for such a bizarre problem.

Idea's anyone?

Thanks,

- Chris

 

[linney]

A couple of things to try.

Windows Network Problem Solver

http://winhlp.com/wxnet.htm

WinXP Connectivity Issues
faq779-4625

Also have you tested XP via "Safe Mode with Networking"?

 

[BadBigBen]

Obviously the next step is to replace the router

No... the obvious next step would be to replace the ethernet cable (the router is working fine with 2000, so it is not a problem with the router)...

and checking out Linney's links the next step thereafter...

specially the section (in the last link) as to resetting the winsocks...





Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[Chris1701]

Gentlemen,

Rereading my original post and your responses, I did in fact leave a couple of things out. I do normally carry both WinSockFix and LSPFix on my flash drive for instances where Malware removal mangles the tcp/ip stack and I've run them both repeatedly and WinSockFix does not fix the problem and LSPFix shows no missing / broken or unusual protocol drivers.

While I did in fact replace the Ethernet cable with a different cable (premade) and one that I've made myself, as I previously stated my cable tester did in fact pass all three cables so I don't believe that this could be a cable issue (all eight wires going straight through) which is why I believe that the next step is to swap the router.

Also this is a middle of the road Dell which uses an integrated Broadcom network adapter. I've got the latest drivers from both Dell and Broadcom and I've deleted the adapter from the device manager and reinstalled both drivers several times and of course I still have the same problem.

But I really have a hard time believing that the router is the problem when the Win2K machine works while the XP machine doesn't. Is it possible that some windows update or patch caused a compatibility issue with the router? The BEFSR81 is an older model Linksys router and the latest firmware that I just flashed it to is from 2004.

- Chris

 

[donb01]

If you're running Windows Firewall look to make sure it didn't block the network at your trouble site or something funky like that. You could take it home and not be blocked because it's a different network.

Next in line, if you're using AVG full-blown internet security with firewall, diapers, body condoms and all those other safety features, the firewall keeps a completely separate profile for EACH network connection. Again, it could be blocking the network at work, but not the one at home because it's a different network.

If you're not using AVG, but are using Norton, McAfee or some other system-invading crap, suspect the same thing and look for firewall stuff.

My suggestion is to temporarily turn off anything anywhere that has anything even remotely to do with a firewall and try again. I am betting that if you're not the primary user of that computer that some message popped up saying something like "The internet is about to give you a colonoscopy - Do you want to block it or ignore?" and the user was afraid to say ignore or just reboot so they chose "block it"....

Been there, done that, got the T-shirt )

 

[Chris1701]

Hi Don:

This is actually a friends home office and about the only benefit is that he uses what I tell him to. (He and his wife have my girlfriend and I over for dinner all the time which is how I get suckered into fixing his problems) Presently he's using NOD32 V4 (which I upgraded from V3 while I had the system back at my home) which does not include a separate firewall. The system does not have any of that security suite garbage which I'm firmly against. I don't like those memory and cpu life sucking packages and my experience is that they are not as effective as NOD32 which does a great job.

I'll take a look at the Windows Firewall configuration tonight and double check to see if it's been set to block anything that it shouldn't.

Thanks,

- Chris

 

[linney]

Next time you are over for dinner take your own Router as an extra guest.

 

[BadBigBen]

with the added info, I would agree with Linney's last comment...

and yes it is possible that older hardware does not get along too well with some of the updated networking stuff in XP (Vista and W7 especially)...

BUT:

When I took the system back to the office and hooked it back up I had the exact same problem.

makes me believe that the fault is still in XP or with a failed NIC...

here you could always hook up a cheap NIC (can be had for a few bucks these days) and test again...

Questions: have you pinged the router, the W2k system, etc...

because another possibility that comes to mind, is that the TCP/IP stack got wacked...

the following is at least worth a try...

How to reset Internet Protocol (TCP/IP)

http://support.microsoft.com/kb/299357

Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[smah]

Perhaps even simpler than another router: a switch (or even a hub). Since the 2K computer (and cable and physical router port and related circuitry....) are functional, connect the switch to the known, working router port, then connect both PC's to the switch.

 

[Chris1701]

That's a really good idea and I happen to have a spare Linksys SD208 eight port switch which I can take over there to test. So I'll give it a try and let you know what happen.

Thanks,

- Chris

 

[karlisi]

In addition - I have Linksys BEFSR81 at home. No problems with Windows XP SP3, SP2, fully patched and unpatched.

Agree with smah about switch or hub. I'd prefer hub with collisions indication. Had a PC with network problem, slow network, sometimes no connection at all, cannot find why. Connected it to hub, 100% collisions on indicator, changed NIC, no problems after that.

===
Karlis
ECDL; MCSA

 

[manhunter2826]

^^I really don't want to deviate from the OP's problem, but I'm always trying to learn. Why would/does the addition of a hub/switch (attached to a router) resolve the PC connectivity problem. I am not suggesting that it does not; it's clear from the above post, and smah's, that it does indeed resolve the network problem with the PC. But why? Thanks.

 

[Chris1701]

Hi Karlis,

Just another piece of information, I really must apologize as I was exhausted when I wrote the original post and left some relevant information out. (I'm swinging by my friends house this morning on the way to another job to try the switch)

In my initial try's to figure out what was causing the problem I did disable the internal Broadcom NIC and install a DLink DFE-530TX+ card. (I really need to pick up a couple 3Com 3C905B's at the next computer show) The results were the same, link and activity lights look good but status of the connection showed that packets were being sent but zero packets received.

It was at this point I was seriously considering that something within the operating system was seriously damaged. I had already scanned with NOD32, SpyBot, ComboFix, HiJackThis! and then run WinSockFix and checked with LSPFix. I also tried running the System File Checker to see if anything critical had been replaced and when that didn't work I did a Repair Install of the operating system, then installed SP3 and all current patches. Unfortunately the problem continued.

Thanks,

- Chris

 

[JonathanMortimer]

Simple test - try the Windows 2000 machine in the other port(s) of the existing router. This should soon discover if there are any obviously duff ports, though it could still be a compatibility problem with old hardware and Windows XP as others have mentioned.

 

[donb01]

I have blown ports on my switch/router on 2 separate occasions over the years - both related to thunderstorms and voltage spikes, so I know it IS possible to fry just one port on a router without messing up anything else. That is a possibility, but then if there is another open port just switching ports might fix the problem.

 

[Chris1701]

Gentlemen,

Since this router does have eight ports and only two computers, I have tried switching ports multiple times (noted above in a previous message) and still the same problem.

I didn't have a lot of time to spend this morning to work on this and just ran over to try the switch idea. Unfortunately this did not work, I did notice however that the status light on the switch port where the router was plugged was flashing very fast as if data was streaming and this was while the XP machine was powered off.

Just another datum, the Win2K machine uses a Linksys LNE100TX V5 NIC but appears to only be connecting to the router at 10 base speed based on the status lights on the routers front panel.

I think that the truth here is that despite the fact that the Win2K machine works (I could try forcing the XP machine to 10 base speed and see what happens) that the router is the source of the problem and needs to be replaced.

Thanks,

- Chris

 

[Chris1701]

Just to close this subject out. I swapped in a Linksys WRT54G in place of the BEFSR81. Needless to say the XP computer started working right away and the Win2K machine continued to work fine.

So go figure, it was the router all along.

Thanks,

- Chris

 

[BadBigBen]

Glad to hear that it is sorted out...

and thank you for posting back with the solution...


Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"