Wireless DHCP is dying

[ixeye]

Anybody else ever had a problem like this?
Windows 2003 Domain with 180 machines,
21 of them with XP SP2 Laptop Wireless
access to the domain, on three different WIFI AP.
Randomly (and luckily infrequently) I am
"losing" my dhcp on wireless machines where
they will "drop" off the network suddenly
and then not reconnect even rebooting, yet
if I change to static IP they will reconnect
fine (I am trying to stem a flow since I
currently have 3 machines started doing this
and I don't want more to start :-)
Also, a user will get the "cannot find a
domain message" on a wireless Laptop machine,
then go over to a wired computer running
dhcp and whoala, on in a flash. In addition,
I login to the wireless clients locally, and
the wireless connection is strong and the
workaround is to change from DHCP to static
ip. So the problem has definitely been narrowed down
to dhcp on wireless. I checked the net and
found a few hits but no fix to this.

Had it happen again this morning (with our one Vista
Business Laptop in the district). I changed to
static IP and immediately works great. AP: Netgear WGT624
and 3COM. Laptops: Daktech 17" Plaidbook and
Lenovo. DHCP: Win2003 Dual Xeon/2 gb. It
seems to be related to something in my DHCP.
For the life of me I cannot figure it out. From the
problem Laptop command line I have tried this:
ipconfig /all : shows 169 ip.
ipconfig /release
ipconfig /flushdns
ipconfig /registerdns (does not work)
ipconfig /renew (will not renew)

I tried the same command structure from a wired desktop and
whoala, works great. Also, I tried wiring a laptop and then
the wired card works great and the commands work fine.
Until today, the problem only occurred on one brand of machine
(lenovo) so I was starting to suspect a NIC driver but
the different laptop threw a wrench in the works. I am trying to
find a DHCP diagnostic to test mine.

BTW, this happened with now 3 different AP (2 Netgear
and one 3COM).

Appreciate the help greatly though.
Thanks,
ixeye

[Dököll]

Anybody else ever had a problem like this?
Windows 2003 Domain with 180 machines,
21 of them with XP SP2 Laptop Wireless
access to the domain, on three different WIFI AP.
Randomly (and luckily infrequently) I am
"losing" my dhcp on wireless machines where
they will "drop" off the network suddenly

Appreciate the help greatly though.
Thanks,
ixeye

Check your antennas...

Test one access point at a time, one may be out of range. Also, if you have a secure network, why not have static IPs within and only use DHCP when venturing out of your network.

If all else fails reboot everything, routers, APs, notebooks, see what happens...

[ixeye]

Right now it seems to be only
happening on this one access
point but a couple of weeks
ago it happened to 3 of four
machines on another AP.
A week before that, 3 of
20 machines.

It is very odd. I have 150 machines
and the 20 varied laptops are the ones
that are "losing" randomly their dhcp through
the domained network. If I change them
to static ips, logout, then log back into the
domain and everything works fine.
What is odd is that this problem does
not happen (ever) to desktops. I can
release and renew ip's all day long on
desktops but laptops are a different
story. My laptops are dying like flies
using dhcp (3 more yesterday). They
have been working fine for several months
but now I have to change all the
laptops to static for them to work
correctly and login to the network.

BTW, rebooting has not helped the problem
so far.
Brent

Check your antennas...

Test one access point at a time, one may be out of range. Also, if you have a secure network, why not have static IPs within and only use DHCP when venturing out of your network.

If all else fails reboot everything, routers, APs, notebooks, see what happens...

[Dököll]

Hey Brent!

Do you know of any changes around you, like new businesses in the area?

Their network may be interfering, I'd need to check into that to be sure. I suspect your access points may need more umf, a boot; if that is, other business are using newer systems.

If this is the case, find out who they are, move your access points around or away from where you are having problems...

More importantly, I would talk to your group about going static. Saves you the trouble, you have more control on what is happening that way. Specific notebooks will always have same IP info, all the time. That's what we do here and it works wonders:-)

[ixeye]

Hey Brent!

Do you know of any changes around you, like new businesses in the area?

Out in a small community miles from any large businesses.
The wireless itself seems to work fine but the integration of wireless and DHCP does not. I am 20 feet from a 3COM 7750 AP. Interestingly enough,
I took one of the laptops away from that AP and moved it to within a Netgear AP on our domain network. It finds an IP and ipconfig choices all work great.
I am starting to suspect 3COM. Unfortunately, I am finding a few cases where the static IP is working for a few days and then it seems to "die" also.
Sometimes it will suddenly come back and other times I cannot bring it
back wirelessly. I am ok with changing everything to Static but this does
not seem to be a global fix :-( I have been working with MX-mode and
power management settings to tweak and make this work but....still the
wired works but the wireless does not :-(

Any other ideas? The event viewer does not seem to give any helpful info, even after ipconfig /registerdns.
Also, I checked for scavenging of the dns records. Is there a dhcp diag tool to check what might be happening?

[Dököll]

Hey Brent!

Do you know of any changes around you, like new businesses in the area?

Out in a small community miles from any large businesses.
The wireless itself seems to work fine but the integration of wireless and DHCP does not. I am 20 feet from a 3COM 7750 AP. Interestingly enough,
I took one of the laptops away from that AP and moved it to within a Netgear AP on our domain network. It finds an IP and ipconfig choices all work great.
I am starting to suspect 3COM. Unfortunately, I am finding a few cases where the static IP is working for a few days and then it seems to "die" also.
Sometimes it will suddenly come back and other times I cannot bring it
back wirelessly. I am ok with changing everything to Static but this does
not seem to be a global fix :-( I have been working with MX-mode and
power management settings to tweak and make this work but....still the
wired works but the wireless does not :-(

Any other ideas? The event viewer does not seem to give any helpful info, even after ipconfig /registerdns.
Also, I checked for scavenging of the dns records. Is there a dhcp diag tool to check what might be happening?

Bummer...

Have you tried getting newer AP firmware?

My router at home stopped functioning, because it was prety old, installing new firmware fixed it, might want to try that. I'll ask around work, see what else it could be:-)

[maverickman4]

why dont you just set all your laptops to a static ip? if it works see if it stays then you dont have to worry about it renewing and creating this problem. if something else happens you can narrow down your problem that way.

what OS are they running? laptops and desktops

[Cyberdyne]

I had similar issues on my network, two things I did was switch my dhcp server to SonicWall instead of the server but still point the DNS to the server and I assigned static ip addresses to all the mac addresses that laptops had, this is great because the laptops are set to dhcp but still get the static address from the firewall =)

Another thing implemented was a terminal server in case the clients needed to connect in emergency situation when domain is not available.

Best luck I hope you get it all fixed ( Try SonicWall and Netgear, I would not mix APs bad idea, also double make sure they are all on channel 4)

Cyberdyne
-=Windows & Networking MOD=-