[OT] Network issues?

[Jesterthegreat]

ok. once again i am calling on the computer skills of the community >.<

at work i have setup 60-80 odd computers in the last few months, and they all setup fine. However 3 or 4 of them have now decided to reject the network! the hub / switch has a light on when you plug it into the computer, so i know the hub and network card see each other. The hub is fine ass all the other computers on the hub work. I have tried using other points on the hub, and i have tried using other network cables. I have tried changing the network cards (and managed to make another PC not work with the same symptoms doing that O_o ) too.

if anyone has any ideas it will be a huge help.

the computers are running Win XP Pro. i have tried fiddling with the IP's etc, i have run IP config on working and not-working machines and matched the settings as well as you can (mine all usually DHCP the DNS server)

i am at a complete loss here, and the staff are getting rather peeved at this. Also there is an inspection later today by the people who gave us the grant to buy these computers and it would be a bit embarassing to say we can't get them working lol

Thanks peeps

[NeoTromb]

Can u ping a working computer from the non-working computer?
If u can! u dont have a TCP/IP problem!

Do u use a win2k domain? If u do, try to delet the computer account in the AD (Active Directory) and re-join the computer to the domain again!

[Jesterthegreat]

no i cant ping the server / a workstation

and yeah im runnin win2k server... ill give that a try after lunch. i wanna collect as many ideas as poss before lunch finishes so i can try them all

:edit: i will post the exact message in a few mins - but it says something like cannot contact domain controller

[BiTeMe]

I have had something similar before but I could still ping. The computers were unable though to join any domains and it only effected Win2k / WinXP machines as the NT4 boxes still worked fine.
Rebooting the switch would clear the error but it would come back every 2 months or so where someone would reboot their computer and not be able to access the domain anymore. Eventualy the switch did this all the time and even after booting the switch it wouldn't clear. Had to get a new switch and I have never had any problems since :)

I would try swapping some cables around so you can get the server and problem PC networked through a different hub as to avoid the suspect one. See if this cures it. If not go back to basics.
Check cables from server to switch, check patch panel cable and check cable from switch to computer. Check IP addresses aren't being duplicated. Set the IP address manualy on the problem PC and check for pings etc...........

[Jesterthegreat]

unfortunatly it is 2 hubs in 2 different parts of the building.

a computer on a 6 post hub (3PC's on it - 2 work fine) and a computer on a 16 port hub (9 PC's on it - 7 work fine)

i have tried new cables etc to no avail.

i guess the next step is to move the PC to a different location and try it in a completely different access point?

[Archeus]

What speed is the HUB and the network cards? It could be one is 10 while the other is 100.

[Jesterthegreat]

nah. besides all the computers are the same so surely all would have the same problem?

they are 60-80 identicle systems

[Stigmata]

but it says something like cannot contact domain controller

have you tried rebooting your PDC or BDC ? can you ping the PDC, we had a similar problem with the PDC just wandering off and siting there doing nothing, not allowing several select machines onto the network.

do you active directory or ?

Andy

[Archeus]

Originally posted by Jesterthegreat
nah. besides all the computers are the same so surely all would have the same problem?

Not always. I had machines with the same network cards but the cards had been set to autoswitching and that caused problems. I just locked them at 100.

If you can't contact the domain controller it could just be a symptom of the network. Have you tried putting the machines into a workgroup.

What happens when you do an "ipconfig". Does an IP address appear?

What network protocols are you using? Try removing QoS packet thingy from the list. If you have IPX/SPX make sure they are using the same types (problem like that years ago, but probably not it just a guess).

If it's XP see that the firewall isn't on in the machines.

Certainly check the machine+cables work elsewhere. Then try taking the Hub to another part of the building and see that it works.

[Jesterthegreat]

PDC? BDC? lol :p

yeah i use active directory

:edit:

nah i keep all the unnecessary protocols etc off the computers - too much hassle >.<

ipconfig gives me the local IP (when not set to DHCP) but doesnt show any info on a connection / server / etc

firewall is off, as i said i set up all personally and they all the same... and i dont want no firewall :p

[BiTeMe]

What about the switch the servers are plugged into?

To test this try kicking a computer that works currently off the domain, release the DHCP lease and set a manual IP (Try pinging with the manual IP set). Then try setting the computer up on the domain again.

Because 2 sperate hubs appear to be suffering then I would assume that these hubs are ok but the switch they are plugged into has b0rked or the switch the PDC/BDC are plugged into have started playing up. I am also assuming you have a main set of switches that you run everything though ?
PDC/BDC ---> Switch bank ------> local hubs -----> Workstation
?? something like that ??
If the crude diagram is about right for your setup then the switch bank would be the place I would be looking for any faults.
There are of course loads of other things that could be wrong, but in my experiance this is where I would start my fault finding based on your 1st post
*edit* PDC = Primary Domain Controller
BDC = Backup Domain Controller
PDC in your case would be your Windows 2000 server that manages the domain
BDC if you have one would be your backup Windows 2000 server

[Jesterthegreat]

yeah thats basically my setup. so should i also try changing leads on the switch bank too?

[BiTeMe]

Try changing leads, but I would start by rebooting the main switches.

[Jesterthegreat]

right ok then

lunch almost over so ill go try some of these ideas in a minute

thanks alot people

[Legoias]

Your problem rings a bell.

We had this at my last office. You dont say if your runnning a 10 or 100mb network.

Try forcing the network card to the same speed as the network and this *should* resolve your problems. After you set the correct speed, do an > IPCONFIG /release and reboot the system.

GL

[Legoias]

Rebooting PDC's and main Switchs:wtf: We would have been hung if we did that, always try and maintain maximum uptime and keep these options as a last resort.

[BiTeMe]

I never mentioned rebooting the PDC. Rebooting the switches should create a downtime of between 5 and 10 seconds depending on how fast your switch is at comming back on-line. Most people will not notice this but it is always good to tell them in advance or save the maintenance till everyone has gone home.

You can always try typing on a cmd line
net send /domain:<insert domain> WE ARE ALL GOING TO DIE!! mwhahaha.. BTW servers will be down in 10 mins for urgent maintenance

[Jesterthegreat]

Originally posted by Legoias
Your problem rings a bell.

We had this at my last office. You dont say if your runnning a 10 or 100mb network.

Try forcing the network card to the same speed as the network and this *should* resolve your problems. After you set the correct speed, do an > IPCONFIG /release and reboot the system.

GL

i have tried forcing it into the same domain and changing the ip setting to what it says in a working PC's ipconfig, but it makes no difference. i will prolly reboot the switch at the end of the day, maybe the PDC at the end of the day too... it hasnt been turned off in months O_o


*edit* will try an ipconfig release

oh and thanks biteme... i wondered how to send a message to all on the network >.<

[Legoias]

No, not forcing the domain name. Look at the NIC settings and look for a box that allows you to set 10, 100 or Auto and set it to the same speed as your network.

It's not about the actull domain and IP but it's interface to the network.

[Jesterthegreat]

hehe tried that too, i also manually set everything to what it should be (except domain obviously - as it wont do it - and possibly server ip as im sure it doesnt see it)

[Jesterthegreat]

Originally posted by BiTeMe
You can always try typing on a cmd line
net send /domain:<insert domain> WE ARE ALL GOING TO DIE!! mwhahaha.. BTW servers will be down in 10 mins for urgent maintenance

does this only work on the server? or on any computer (assuming i am logged in as an administrator)

:edit: and do i have to type the .com on the domain name? (you do for somethings, not for others)

[BiTeMe]

Yes you need to be logged as administrator (havn't tried another user o_O )
I don't think you need .com but I have never had the need to setup DNS on our networks so I can't be 100%