[Vi7ER]

This is a problem that has been annoying me for some time now...

I'm running a network of about 150 winXP clients, about 30 of which are laptops that may connect via two NICs at times (wifi and LAN). I have DHCP and DNS sitting on windows server 2003v2 AD Domain Controller with a scope of 512 addresses.

What seems to happen (still no idea why after many hours poking around) is that suddenly an IP address (often on a wifi NIC, but sometimes on a wired NIC) will become unable to reach the domain controller. By this I mean network shares become inaccessible, users cannot log on and I cannot ping the server from the client or the client from the server.

However I can still ping other clients; from the server and the client with the problem. Furthermore it is often the case that the other NIC on the problematic client will be able to maintain the connection no problem. As it has a different IP address it is able to reach the DC with no problem.

So what is basically happening is that the communication between a specific client and the DC only is being blocked somehow! I'm tearing my hair out! It doesnt make sense.

My only solution so far (which works everytime) is to set up an exclusion on the IP address this is occuring on and then renew the connection on the client. Now, this does not even work first time and I often have to exclude a string of IP addresses temporarily until I find one that allows full communication! Interestingly the DHCP server will happily provide IP addresses (next available in the scope etc) and then be completely unable to ping that IP address or recieve pings from that IP address.

If I try to ipconfig renew the IP on the client without excluding the current IP address from DHCP scope first it will invariably come back with "cannot connect to DHCP server"!

I've considered the possibility the problem lies with the networking hardware, switches etc, but then, i have another server connected to the same switch as the DC which I never fail to ping!

Anyway thats about it.

I would very much appreciate some thoughts or tips on what I can do! I've played with various sniffer programs, netstat, tracert, netsh etc but they dont seemed to have shed any light on whats going (or perhaps I missed something).

Feel free to ask for more details if you're inclined to help! I'd be more than happy to elaborate. This thing is doing my head in!!

[nfedei]

This is a quite complicated scenario you have going on here...
Every network is configured differently, and if I'm correct the problem may lie with simply the computer name. I know this sounds crazy...but I believe the default setup of the server only allows the same computer name to obtain one IP address at a time...even though you are getting two ipaddress.. Where in your case, you have the same computer connecting simutaniously to the network with the same computer name. This may in turn be causing the failures you are speaking of...I hope i'm on the right path here..
My suggestion would be to have the users with laptops disconnect there wireless device while connected hard wired or simply stay wireless...

[Vi7ER]

Hi nfedei,

Thanks for the response! You're thinking along the same lines that posters who have replied to another identical thread I started are!(http://www.computing.net/answers/net...ing/37208.html)

Which is good obviously good as it helps with to nail down the problem. Only thing is that the issue recently presented itself on a desktop computer! Which throws a spanner in the works.

The other thing is, that laptops generally only ever get connected via cable when they wont connect wirelessly.

If you have time, you could have a read of the thread at the link above and see if makes things a bit clearer.

I hope you can help, and it will be much appreciated, as I've been struggling with this for a long time! It's really bizarre.

Cheers

T

[srhoades]

The multiple IP's to a host name is a non-issue because DHCP hands out addresses by MAC address, not by host name.

As to the real problem I'm still thinking.

[nfedei]

No problem. I'll take a look at it here later and see if I can make some sense of this to help. Sorry you are having this problem! I'll repost here soon!
Thanks
Nick

[srhoades]

Why don't you give is some more information on your topology? Make and model of switches, how many you have, speed of the network etc. When this occurs you say you can still ping the other workstations but all communication to the server is down. Is this the only server you have? The server may just be overloaded. 150 workstations with the server handling all the requests, it just may be a bottleneck.