Dell Wireless 1490 Dual Band WLAN Mini-Card will not get IP address (ignores DHCP OFFER packets)

This is ridiculous. My Dell Wireless 1490 Dual Band WLAN Mini-Card on a Dell Precision M90 Win XP SP2 just refuses to grab its DCHP address half the time from public access points. Everyone around me is humming away with no problem. I've got it configured as DHCP, everything default, but it doesn't work. During a "repair" or a "ipconfig /renew" I can see that it does indeed receive a couple of packets, but it's doing nothing.

If I run Ethereal/Wireshark I see that the DHCP server is sending two DHCP OFFER packets to my machine, but my machine just ignores them. This seems to happen in half the public access points I go to (over which I have no control), and it's inconsistent. Some days it works, some days it does not.

Do I really have to run Wireshark and dissect the DHCP OFFER packets to manually configure my Wireless Ethernet card every time? Is there some mysterious configuration parameter that will help solve this?


- Disgusted with Dell

Reply to
Jennifer R
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Jennifer R hath wroth:

What is rediculous? The problem or the question?

Let me guess. This only happens when you've successfully used your laptop at your home or office, and then go to a coffee shop?

This is sounding familiar. You're close.

Right. Let's blame Dell. The first step to solving a problem is to blame someone. Dell will suffice for now.

I'll assume that the coffee shop is not running out of DHCP addresses. I created this problem at some of my coffee shop hot spots using DD-WRT by specifying that DHCP save the leases in NVRAM. That worked until I filled up all the slots, where it decided that it didn't want to add any more clients.

You were close. Try this next time: Start -> Run -> cmd ipconfig /release (wait a few seconds) ipconfig /renew ipconfig (to display the results)

What is happening is that Windoze XP SP2 thinks you're still at home or work and is trying to renew the previously assigned IP address forever. This is especially true if the IP address of the access point is the same at work, home, and at the coffee shop, a common problem. The DHCP requests are done with MAC broadcasts, but the renewals are done using IP addresses.

This was fixed in some obscure wireless networking update from Microsoft. It was also an issue with some wireless clients and drivers. Check if you have the latest drivers and wireless updates.

You might also wanna try a DHCP tester at:

There's a bit of a trick to using it. Type in literally anything into the "Device Identifier" field. Check the "Request response" box. Don't check the "Use BOOTP" box. You do NOT need to be connected for this to work. Mine returns: option PKT:Opcode=2 option PKT:HType=1 option PKT:HLen=1 option PKT:Hops=0 option DHCP message type=5 option PKT:Flags=32768 option PKT:Seconds=0 option PKT:XID=41 option PKT:SName= option PKT:Boot file= option PKT:CIAddr= option PKT:YIAddr= option PKT:SIAddr= option PKT:GIAddr= option PKT:Magic cookie= option Subnet mask= option Gateways= option Domain name servers= option Broadcast address= option Server identifier= option DHCP address lease time=7200 option DHCP renewal time=3600 option DHCP rebinding time=6300 option PKT:CHAddr=00 which is rather interesting as the machine I'm running it on has a static IP address. Also, the results are rather "interesting" if the coffee shop has more than one DHCP server running.

Reply to
Jeff Liebermann

Thanks for the link to the software. I downloaded it yesterday and checked it out. However today my DHCP *is* working from this particular coffee shop, so I'll have to wait for the next problem before I enlist its aid.

I *have* tried the /release /renew pairing, many times. I usually use the "repair" option, which does more than that release/renew -- it disables the adapter, clears various caches, etc. I agree with Microsoft's "repair" philosophy -- they clean the slate and start over. (I actually met the guy who implemented the XP SP2 wireless code for MS, at a national park in Panama of all places. I thanked him profusely for the vast improvement over the previous implementation. He probably gets that a lot.) I used Wireshark to examine what happened during the /renew, and that's when I discovered that the router *was* offering a DCHP configuration, but that my laptop was ignoring it for some reason.

I suspect this utility will merely tell me what's > Jennifer R hath wroth:

Reply to
Jennifer R

Jennifer R hath wroth:

Run it to see how it works. A fun test is to intentionally set you laptops IP address to some random IP that is guaranteed not to work with the hot spot. Then, run the DHCP test program. It should still work (because it uses broadcast packets).

Ummm... it's "repair". "Repairing" is what you do with a BlueGoof headset or device.

IPCONFIG /flushdns will clear the DNS cache. However, that's not causing your problem. My guess(tm) is that since your MAC address is no stored in the unspecified model coffee shop wireless router's DHCP lease cache table, it will continue to work at this coffee shop until some other customers has the same problem, complains to the manager, and they reboot (or flush) the router. As I think I mentioned, I've created this situation using DD-WRT which was not fixed with a power cycle (because the DHCP lease table was saved in NVRAM). You can sorta verify my guesswork by recording what IP address the DHCP server delivers at this coffee shop. If it's always the same, then my guesswork is correct. If it's fairly random, I'm wrong.

I would have cursed him and his accomplises for a variety of abominations. The most disgusting is that for many years, Microsoft has promoted the idea that computers have IP addresses. This is incorrect. Interfaces, such as ethernet cards, wireless cards, cell phone cards, and such have IP addresses. It took several years and a few revisions to get that straight. Recently, there was an un-necessary change in how Vista uses DHCP with accompanying failures to obtain DHCP leases. The MAC layer network and wireless diagnostics in W2K and XP are almost totally missing. There have been substantial improvements with Vista but nothing resembling an industry standard management protocol (i.e. SNMPv3) that is suitable for monitoring MAC layer errors (necessary for wireless error detection). Etc... etc...

Dunno. Please don't send me the capture file. I don't have the time.

Correct. All it does it test the DHCP server.

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