Really weird network worries

[Gollum]

Hi! My home network is about to drive me nuts. I mean I've been running a home network for well over 10 years, so I know the basics, but currently it just won't work reliably. And I'm completely lost!

The setup is 2 desktop PCs, both running WinXP SP2, all latest patches installed. I'm currently on a WLAN, everything is set up correctly to the best of my knowledge. Both PCs can see each other and access the internet through the router. The problems begin when they're trying to access each other's folders or printer. Sometimes I can get access right away, the next try I'll only get a "network resource not found or you have no rights to access this resource" pop up. TCP/IP is set up with fixed IPs (no conflict), PCs are in the same workgroup, all important drivers and protocols are active, I have given the correct rights to the shared folders (again, to the best of my knowledge, which is "everybody" has access rights set in the non-simple NTFS options), I've set up identical user accounts on both machines (WITH passwords and access rights), disabled the XP firewall and tried many other tips from guides and threads all over the net. The network performance has actually increased lately (used to be very laggy), but its still a hit and miss affair.

And that's what's driving me nuts! It used to be, back in the "golden" Win98 days, that the network either worked or didn't! Now, it works for 2 hours - then doesn't for 10 minutes - then it works again for a few minutes - then it completely shuts down - when I get it working again its often fine for like half a day - only to break down again from one second to the next, without any reasons I can think of. I mean nothing changes AT ALL! To the best of my knowledge the behaviour is completely random. No programs are started on either PC when the connection breaks down, the WLAN connection stays intact on both ends. Both PCs can still access the internet through the router, they just can't access each other anymore. One second I can send a ping to the other PC, the next I can't anymore. Isn't that a bit weird? I don't think its a WLAN issue, we had a regular LAN setup before that and it was also a bit dodgy. It only it didn't bother me as much as I wasn't using the network a whole lot for a couple months.

I'm really starting to go mad over this issue now though, especially since I currently rely on the network for both printing and php development. Does anybody have ANY idea what might be causing this? Possibly a virus or trojan? I do have an auto-updating AV Guard running on both machines 24/7, scan with a-squared, spybot S&D and check my processes with Hijack This! regularly. Are there even viruses that could cause this sort of odd "network disturbance"?

I like to think I know my shit and usually I'm the guy everybody goes to when he has trouble with his PC. But I feel completely helpless and frustrated right now. Help me PLEASE!

 

[stevem]

Peculiar. Have you turned off simple file sharing? Is QoS enabled/active? What gateway/wireless router do you have? You should have no probs setting up one router as DHCP server & config PCs with dynamic/fixed/static IPs. Are all the devices in the same sub-net?

 

[Gollum]

Peculiar.

I'd say so.

Have you turned off simple file sharing?

Check, and it has improved the situation, but not fixed the problem. I can get access more reliably now, but the PCs still "dissapear" at random intervals, only to "reappear" after a while (sometimes a minute, sometimes half an hour).

Is QoS enabled/active?

Yes.

What gateway/wireless router do you have?

Right now I'm using the Sinus 154 basic router from T-Com. I had the same problem with the Speedport W700V and my old wired LAN switch too, though I haven't tried using them for a couple weeks, sicne everything else works just fine. I might try the other devices again when I've got some spare time on my hands.

You should have no probs setting up one router as DHCP server & config PCs with dynamic/fixed/static IPs.

I did that, but the dynamic IP allocation was a bit too slow for my tastes, sometimes it would take over a minute to negoatiate an IP, so I decided to give them fixed ones be done with DHCP. Does DHCP hold any advantages over static IPs? It's not like I regularly add other PCs to my network (only the Xbox360, but Live works like a charm too)...

Are all the devices in the same sub-net?

If you mean the subnet-mask (255.255.255.0), then check...

 

[MatiasZ]

How are you trying to access the other PC, NetBIOS or IP? If you are using NetBIOS, check what WINS config you are using. It should work more consistently via IP, so I would try it that way first.

Example: use \\192.168.1.15\myFiles instead of \\PC2\myFiles

 

[Gollum]

I do have NetBIOS explicitly activated in the TCP/IP WINS driver tab (changed it from standard setting to always on, some webguide advised that). I don't really know what it does though, maybe you could explain it a bit? The way you asked made it sound like it might be part of the problem, because I found out that often I can't access the PC by name, but can by IP. So I'm currently resorting to entering IPs manually. When I type \\computername\htdocs I get an error, yet when I type \\192.168.2.14\htdocs I get in instantly.

Also I seem to have traced the problem to my secondary PC. The network has been runnign more or less stable the past 24 hours, except for periodic intervals, when I suddenly can't reach the 2nd PC anymore from my primary PC. I can't access its webserver anymore and don't even get a ping from it. As soon as I start a ping from the secondary PC to the primary though, it "reappears" and can instantly be accessed fully again. I've tried that about 5 times by now and it has worked every time. Still annoying, but at least a temporary solution. I'd still like to fix it properly though.

 

[Frank]

1. Completely throw away the networking protocols on both computers, uninstall the network adapter and reboot. Windows should automatically reinstall them, check if TCP/IP is installed and if not, add it. Reassign the IP adresses and look in the router for the DNS servers. And get rid of QoS. That should fix it.

2. If it still doesn't work, try adding the other computer in the C:\WINDOWS\system32\drivers\etc\hosts file, on both systems. That should fix it. If it doesn't, try using the router as the first DNS server.

3. If that still doesn't fix it, try "nslookup google.com" and "tracert google.com" from a DOS-box a few times, and see what happens.

 

[MatiasZ]

Definitly, as DiGuru said add both PC's to the HOST file in each PC, as in:

Host file at PC1: add the line
"192.168.1.xxx pc2_name" where xxx is the last part of the IP of PC2

Host file at PC2: add the line
"192.168.1.xxx pc1_name" where xxx is the last part of the IP of PC1

The spaces between the IP and the name of the PC should be a TAB. This should fix the problem. This is because you don't have a WINS server anywhere on your LAN, so your PC doesn't know where to ask for the IP that answers to a specific name. Sometimes this is done by the router, sometimes Windows works as it should and makes a network discovery, but it could easily be (now that I think of it) that your network discovery service is not started on PC1, so you can check that too under Administrative Tools->Services (don't remember the exact name of the service but look for the description of something that "fits" this )

 

[Gollum]

Gonna try that out tomorrow, thanks guys!

 

[Martin Eddy]

Definitly, as DiGuru said add both PC's to the HOST file in each PC, as in:

Host file at PC1: add the line
"192.168.1.xxx pc2_name" where xxx is the last part of the IP of PC2

Host file at PC2: add the line
"192.168.1.xxx pc1_name" where xxx is the last part of the IP of PC1

The spaces between the IP and the name of the PC should be a TAB. This should fix the problem. This is because you don't have a WINS server anywhere on your LAN, so your PC doesn't know where to ask for the IP that answers to a specific name. Sometimes this is done by the router, sometimes Windows works as it should and makes a network discovery, but it could easily be (now that I think of it) that your network discovery service is not started on PC1, so you can check that too under Administrative Tools->Services (don't remember the exact name of the service but look for the description of something that "fits" this )

It's called "Computer Browser". You also need to make sure the service "Server" is started as well.

It's definately the best option to allow the router to be a DNS and DHCP server.

 

[stevem]

Gollum, there's no need to complicate things with static ips & lmhosts files. You can set your router as DHCP server with never expiring leases. There's no need for QoS unless you have a specific requirement (eg VoIP), but the default setting won't harm bandwidth. It can be manually set to 0% or disabled if concerned. With WinXP, there's no need to explicitly set NetBIOS over TCP/IP. Just leave the setting as default & enable DHCP at the router. Are you using VPN to secure the wireless endpoints?

The fact that DHCP IP allocation takes that long leads me to believe you have a router config issue. I assume you have DSL or cable? If DSL, check that the modem is set to bridged mode & have your wireless router connecting via PPPoE & acting as NAT/DHCP/SPI. There's usually no need to set DNS/Gateway/WINS internally, as this will propagate from your ISP. Just set to auto. Alternatively, you can set the DSL modem to connet via PPPoA/PPPoE & enable NAT/DHCP/SPI. Then set your wireless router to operate as an AP only via one of its LAN ports, not the WAN port, & disable DHCP/NAT on the wireless router. Also set their IP addresses to the same net, eg 192.168.1.1 & 192.168.1.2. Another sometimes useful option is to set DSL modem as per normal, & then config DMZ with the static IP of your wireless router. You'll need to config DNS & gateway manually, but the wireless router can be connected via its WAN port. It's easy to play around with sub-netting, too. The worst case scenario is having double NAT/DHCP. If you have a cable modem, it's already operating in bridge mode when connected to the CMTS.

If you have a mixed network, it's possible that you have a master browser problem. In this case you can try disabling the computer browser service on the more problematic pc. I'd be surprised if a multi-homed or RAS PC was the source of the problem. As always, get the latest drivers for your NICs/WNICs & latest firmware for your DSL modem and wireless router. You may want to try disabling power management options for the NICs, too.

 

[Frank]

Yes, i agree that it is best to have the router do DHCP and DNS. But I assume he already tried that.

And I strongly disagree with using the router only as an access point and disabling NAT, as that causes a lot of unwanted traffic and port attacks.

 

[stevem]

And I strongly disagree with using the router only as an access point and disabling NAT, as that causes a lot of unwanted traffic and port attacks.

Where did I suggest not protecting the LAN from WAN side traffic?

 

[Gollum]

Just wanted to thank you guys again for you help! B3D is simply a community of some of the best and most helpfull people around. Cheers!

Something I did while trying to fix the issue has resolved it. I don't know what exactly it was, as I was trying out many different things, also from this thread, and from the day of my last post till today, the network has been stable. I didn't get as far as re-installing all the protocols and I still use my static IPs. Its a great relieve TBH. Finally I can actually work instead of getting up and fiddling with the other PC every 15 minutes.

Now its only IE and Firefox that drive me nuts, why do they interpret CSS as differently as they do? Oh my, at least I get paid for figuring that out, unlike the network problems.

 

[Frank]

Now its only IE and Firefox that drive me nuts, why do they interpret CSS as differently as they do? Oh my, at least I get paid for figuring that out, unlike the network problems.

Join the (large) club.

 

[Martin Eddy]

now its only IE and Firefox that drive me nuts, why do they interpret CSS as differently as they do? Oh my, at least I get paid for figuring that out, unlike the network problems.

Because IE doesn't follow standards. I'm just glad I only do 1-2 websites a year. I'd go bonkas if I had to deal with it every day.

 

[Frank]

IE is a large set of different standards all by itself.