XP laptop - wlan only gets DHCP address when cable plugged in?!

[sparkeh]

Ok this is a bit odd.

 

I have an XP laptop. When you start it up the wlan connects but can't get an IP address from DHCP, it just times out.

However, if I plug in a network cable, the wired NIC gets an address, then the wlan NIC gets an address, and then just works.

If I remove the cable the wlan works fine.

 

Any ideas why it won't get IP over wlan?

[chazzy2501]

if your wireless is on a VLAN I'd check the DHCP helper. It is possible to block broadcast packets on some APs as well. (thus breaking DHCP)

[sparkeh]

Good idea, but no vlans here

[chazzy2501]

have you checked the laptops wifi mac address? Maybe it's invalid (if you changed its address in the drivers)

[sparkeh]

Hmm no everything seems ok MAC address wise.

[sparkeh]

Ok bit of an update.

I ran wireshark to take a look at what was going on with DHCP, it seems that the client is sending a request, the DHCP server is braodcasting an offer, but then the client is sending another request, the server sends another offer, etc etc etc... until it times out.

So looks like, for some reason the client isn't picking up the offer?

[sparkeh]

Right, seems to be a bigger problem. Even with a static IP it can't ping anything, only itself...

[mac_shinobi]

Is windows managing the wireless network side of things ( wireless zero config or whatever it is called now ) or has it got a utility of some description installed which has taken over managing wireless connections whether it be Intel / Access Connections or whatever ) ??

 

If that is the case - may need to get the utility to let windows manage wireless connections.

 

Also a bit of shooting / jumping in the dark here but possibly also

 

* Disable windows firewall for domain / work / home etc on the client

* Ensure the wireless network card ( control panel --> Network and Sharing Center --> Manage network connections or adaptors --> right click on the wireless card --> properties --> ensure its set to DHCP for IPv4 and possibly disable or at least uncheck IPv6 ( if you don't need or use IPv6 )

 

Edit - This part should read ( control panel --> network connections --> right click wireless network card --> properties --> set to dhcp --> etc etc ) , above is obvoiusly for windows 7, my bad !!

 

As a last resort reset

 

* Winsocks

* TCP/IP Stack

* Reset the hosts file

 

Guide ref the first 2 points above ( SG :: How to repair TCP/IP and Winsock )

 

Can post back with guide on how to do the above three if required although netsh for the first two and then just a case of using notepad to reset the hosts file ( so not overly complicated )

 

The first two require a reboot before taking effect.

 

If using a wireless network utility such as Intel / Access connections etc, it may be an idea to export / make a backup of all WiFi Profiles and then delete / remove all of them and re add the wireless profile and try and connect again ?

 

If it is still an issue then I will stay subscribed as would be good to know the solution

 

Edit - may also be worth while updating the wireless card driver ( from the manufacturers website ) whether the manufacturer of the wireless card or the manufacturer of the laptop ??

 

May also be worth while scanning for malware / viruses on the laptop

 

Possibly not likely as you mentioned that it did get a dhcp address when the laptop was physically connected to the network via cable however :

 

Edit - I presume the MAC Address for either of the network cards on that laptop has not been put in DHCP to hand out a fake / dodgy ip address etc ?

Edited October 7, 2013 by mac_shinobi

[sparkeh]

Progress!

So resetting TCP/IP followed by renewing IP from DHCP works!

 

However, if you reboot, then it fails again so needs another reset...

[mac_shinobi]

I would update the wireless network cards driver and try again. I've had a few laptops where ive done the reset not work but then dhcp starts to work after re-installing / updating the network card driver

[mac_shinobi]

If the network card driver and nothing else helps / fixes the issue - I know this laptop has XP and not windows 7 and the below thread is related to windows 7 ( ref this thread here : http://www.edugeek.net/forums/windows-7/60087-win-7-dhcp-netlogon-firewall-microsoft-confirm-bug-4.html )

 

Just curious if the DHCP registry key or the setting on the intel wifi card may help ref your problem / issue ?

[sparkeh]

Thanks @mac_shinobi for your help.

I think that a combo of resetting the stack and updating the drivers has solved this now. Rebooted a few times and still seems to be connecting

 

Cheers!

[mac_shinobi]

no problem Annoying when things don't work.