Cannot get DHCP address - "No DHCPOFFERS received."
 

I'm running Kubuntu Gutsy Gibbon on a Dell laptop with a Linksys WPC54G v5 PCMCIA card (Marvell chipset). I actually got wireless networking going with a V1 version of this card (Broadcomm chipset), but I needed to change the card to v5 for reasons not relevant here. My router uses WPA-PSK security, and it works just fine for a wired connection to the very same laptop. It also works just fine for a wireless connection under Windows XP.

I can get a connection validated but I can't get the router to send an IP address. According to KWifiManager I have a strong connection, the SSID has been correctly identified, and an access point MAC address is available. The one thing that's not available is the local IP. I'm running wpa_supplicant, and ps -A shows that it is actually running.

I have another laptop running on the same network, also using Kubuntu Gutsy Gibbon, that works just fine. It has a built-in wireless chip. And at one point I actually got the v5 card to work correctly, but after a reboot I could never get it to work again!

Here's the contents of /etc/network/interfaces:

Here's the result of ifconfig and iwconfig:

Here's the relevant part of dmesg, showing the activation of ndiswrapper:

And here's what happens if I call ifdown and then ifup:

One other thing: I can get the card to work with a fixed IP address, but that's not a satisfactory solution for several reasons.

So how can I get DHCPDISCOVER to work?

Intermittency
 

After fiddling around with things that made no apparent difference, I got the card to work after bootup -- twice. Then, on the third bootup, it didn't.

So I tried something else: resetting the router. That seemed to make it work again, but there's no way to know what the future will bring.

The problem is back
 

Alas, after upgrading to Kubuntu Hardy Heron the problem is back, and this time resetting the router (and the cable modem too) helps not at all.

Can someone interpret this output from wpa_supplicant?
 

I still have the problem with being unable to connect with my wireless network from Linux because I can't get a response from DHCP. It happens on two different Dell laptops, both of which have Linksys PCMCIA plug-in network cards. I even tried replacing the router, but that didn't help either. So I tried stopping wpa_supplicant and starting it again in debug mode. I suspect the output will reveal just what the cause of the problems is, but I don't know how to interpret it. Here it is, with repetitive parts deleted:

Help with this persistent problem would be much appreciated.

same issue
 

I think I have the same issue as you. I cannot get a DHCP ip address on my IBM thinkpad x60 unless I reboot my router.
Once I reboot, things work fine. My XP laptop has no issues connecting to the router, and the problem only started
happening after I upgraded to 8.04 (Kubuntu). I am not near my kubuntu laptop, so I will try to go over my logs later on.
My wireless card is an atheros something, and my router is an SMC something.

Reboot doesn't help now
 

It used to be that rebooting the router solved the problem, but no longer. In fact, I even tried replacing the router, and that made no difference either (but it cost me $30 or so).

It does seem odd (and probably revealing) that the behavior should be affected by the state of the router, given that the router can respond perfectly well to DHCP requests from Windows.

The secret probably lies in that long output I posted, but I have no idea how to interpret it.

It looks like your card associated with your AP just fine.

I see eth0 is also receiving an IP on the 192.168.0/24 network. Where is this DHCP server?

And is this DHCP server different than the one used/provided by by your AP ?

I sometimes have a cable connection also
 

I had noticed that the card could associate with the access point, though it would drop that status after a while. But that didn't get me the DHCP-assigned address.

Sometimes when I can't get the wireless to work, I hook up the Ethernet cable, which is much less convenient. That accounts for the eth0 connection. If the wireless worked, I wouldn't be bothering with the cable.

Not obtaining a DHCP lease is the symptom, the problem being association issues with the access point.

It is DHCP that gets the focus, because there error messages tend to focus on failure to obtain an IP.

Association seems to exist but doesn't yield an IP address
 

Any suggestions as to how I can track that down? As I noted earlier, I do get an association, at least some of the time, but it never yields an IP address.

That makes a lot of sense to me.

If you believe the association is reliable, configure your system with static IP information, and see how reliable the connection remains.

I've seen DHCP bugs in certain routers, where firmware updates resolved the problems. I don't know that is the case here.

I've attached a copy of my logs (from ksystemlog). Worksheet 1 shows a successfull DHCP lease after rebooting the router, Worksheet 2 shows a unsuccessful attempt. XLS of log output

Sorry, I won't open Office files from unknown origins. Just put your data into a text file. No reason to use Excel.

was an open document saved as an xls, but here is a ods

ods of logs

kptkill,

I don't see any oddities in the diagnostics from NetworkManager.

I presume AccessPoint1 is your AP.

The DHCPDISCOVER messages are being sent; whether they are being received but ignored on the AP, or not received at all can't be known from the output. Does your SMC have any logging? Can you see if there are any errors, events, or anything that indicates what is happening on the AP ?

From NetworkManager, try disabling any other Ethernet devices, and the wireless. Wait a moment, and then reenable the wireless.