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Client PCs timeout when using internet or LAN but they are getting IP addresses from DHCP fine.

Posted on 2006-11-14
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We are having a weird problem. We have a LAN setup for our school. The computers in student dorms are getting IP addresses from our DHCP server but they are not able to surf internet. Sometimes it loads pages, sometimes it doesnot. I tried to ping our main server and outside website and it gets a reply few times and times out few times. Client computers in other buildings are working fine. If I use static IP address on a computer in dorms, it still does the same thing. They get connected and sites load sometimes and other times they time out. We have to Domain Controllers on 192.168.x.x address. We have a superscope setup and students are on 10.0.x.x scope while faculty and staff is on 10.10.x.x Any suggestions?? Everything has been working fine. The last thing i remember doing was adding a reverse lookup zone in our primary domain controller. That zone is already in our secondary domain controller. I am not sure if i can just delete it from our primary DC because it says it is active directory integrated zone and it will be deleted form AD too. any help???
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Question by:ASMS_Helpdesk
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by:jessmca
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Are there any errors in the event viewer on the PDC?
What are you using for your gateway / firewall?  Do you have any monitoring software to see what traffic is being used?
What are the switches indicating regarding heavy traffic or collisions?
What services are you riunning, mail, web, ftp??
Does the problem persist when the mail server or any server is disconnected?
What if you disconnect a section of the network, does it make a difference.  If ping -t is failiong every other, leave this on the screen and try disconnecting various servers etc.. and see if it improves.
What have you tried so far?

Jess
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by:camacho_marco
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Are you running wireless????  Or how are you interconnecting the dorm to the site????
I think you a medium problem.

CHeers
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by:dlangr
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If you do not want to unplug all your devices:

run ethereal ( www.ethereal.com ) on a computer experiencing the ping timeouts. Look for traffic that seems to be out of place or excessive. Locate the device causing it and unplug it to see if that resolves the problem.

If you do not see excessive traffic you might have a bad cable or network interface somewhere between the machine you are pinging and the machine you are at. try replacing cables / network cards and routers along the route if you are unable to find the cause.

If possible connect to the web or console management interface of the router between the two networks and run a ping to computers at both networks and see if that works without problems.


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by:dlangr
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about the AD integrated zone:

If you delete it at one DC, it will be deleted at the other DC's as wel, as AD replication will take care of this.

back it up first . see http://www.jsifaq.com/SF/Tips/Tip.aspx?id=5695

You can recreate it and import the backup to restore it.

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by:ASMS_Helpdesk
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More detail...
     The student section is 10.0.x.x so everyone on that section is experiencing time outs. If i ping one of the switches on that section it timesout and gets reply intermittently. I will try ethreal.
     Wireless is 10.20.x.x section which is working fine.
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by:dlangr
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another way to back it up (and you should have a recent backup of this at all times) is to back up active directory. You will have to do an authorative restore to restore the zone though.
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by:ASMS_Helpdesk
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More detail...
     The student section is 10.0.x.x so everyone on that section is experiencing time outs. If i ping one of the switches on that section it timesout and gets reply intermittently. I will try ethreal.
     Wireless is 10.20.x.x section which is working fine.
     10.10.x.x which is faculty staff is working fine too.
     If i do nslookup on the switch on 10.0.x.x section it says that our DC cannot find it or non existent domain but sometime i do get reply from it. Same thing with other computers on that network. We dont have 10.0.x.x or 10.10.x.x reverse lookup zones defined so I don't know if that matters because 10.10 works fine. I will add more information as i figure things out. Thanks for suggestions and help.
     
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by:dlangr
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as you tried servral switches on that section, it is probably some kind of broadcast on that section that is clogging up your network and / or network equipment resources. Should be very evident in ethereal, especially at low-traffic hours.
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by:dlangr
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sounds like your dns server is unreachable most of the time or is so overloaded that it does not answer to the requests... check the system resources on you dns server and try to ping from the dns server to the problem pc's by ip, not host name.
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by:ASMS_Helpdesk
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dlangr: I tried to ping a computer on student section from dns by both name and ip and it times out. System resources are normal.
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by:jessmca
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I dont think there is a DNS of software issue. You have a DNS going on on the stiudent section.  Could be faulty hardware such as a switch or computer in that section.
Do you have a spare switch you could try replacing the main switch with?  What about the logs on the router for the student section?
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by:jessmca
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DOS I meant

Does the ping get through usiung ip address?
If not, then forget DNS for the moment. if the network isnt working and pings to ip addresses time out, you can hardly expect DNS to work.
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by:dlangr
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ok, not your dns server or other name resolution problems then, let me know the results of running ethereal.
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by:camacho_marco
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The problem is you Switch or the way you are cable or fiber, it is not a Software or DNS problem is Hardware problem.

Cheers
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by:ASMS_Helpdesk
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Ok i have the ethereal file. I am new to ethereal so i wasn't able to find anything strange. I can email it to you. Strange thing is that the setup was working fine few days back.


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camacho_marco earned 250 total points
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Dis you tries to replace the wire, or fiber??????????????
The switch??????
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by:dlangr
dlangr earned 250 total points
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e-mailing it to me is considered an unfair advantage. please read "Using email to resolve a problem" at http://www.experts-exchange.com/help.jsp#hs8

from the article: "The solution is to load it to any of the free websites out there, and then post a link to it "

some examples:
http://www.yousendit.com/
http://www.50megs.com/
http://www.150m.com/
http://www.streamload.com/
http://www.sendthisfile.com/
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