connections drop but ping and nslookup still work

[CaptNeo]

I have a weird connection on two of my computers. Here are the details.

I'm running dhcp server and nat on my router.
The two computers gets ip from the dhcp server (router).
I can ping my inside and outside dns server as well as do an nslookup (of any hosts on the Internet) without any problem.
Using Windows 2000 server as my inside DNS.
Using Windows 2000 workstation (two computers).
We don't use a proxy server.
I can ping all the computers (other computers) on the network and all the connections on the router.

Now the problem is when the next day we come in (the two computers were left running all night), we can't browse and I can't check our email (outlook) but we can still ping and do an nslookup.

The only way that I resolve this problem is when I do

ipconfig /release
ipconfig /renew

Does someone know what going on? I'm not sure if this is the right place to post this question. Please someone let me know if I should also post this on a different forum.

Thanks.

 

[larshald]

Hmm... CaptNeo

That is a wierd problem.

To narrow down the problem i would setup one of the computers with a static IP address and options (as set by the DHCP server). Then let the machines run overnight and the following morning see if there is a problem on one or both of the computers.

If the computer with DHCP cannot browse and the other one can i would look at the DHCP server. Maybe something with the renewal of the lease time or a problem in Windows.

If both the computers fail maybe you have a faulty router or a faulty firmware in the router. I have heard of D-Link DI-604 doing something like this, and all they needed was a firmware upgrade.

Hope this help.

\Lars

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Why make things difficult, when it is possible to make them cryptic and totally illogic, with just a little more effort.
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[CaptNeo]

I have a feeling that it's not the dhcp server that's causing this since I can still ping all ip addresses including those outside of our network and I could also do an nslookup even those outside of our network.

I'm using a cisco 1721 router btw.

I appreciate your answer though.

 

[larshald]

You might be right about the DHCP server.

Could you let me know how the experiment worked out...

Does the internal DNS server forward requests to rootservers or does it use the standard rootservers ? \Lars

 

[Whoheard]

IF you reboot the router, does it help?

Bob

 

[CaptNeo]

I have a Windows 2000 server as our Internal DNS Server and the outside DNS Servers were provided by my ISP. Like I said I have no problems resolving hosts outside our network so the DNS don't have any problems.

 

[CaptNeo]

I haven't rebooted the router yet. I'll try that and see it something happens.