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lilsirecho

Veteran

Registered: 2003-10-24

Posts: 5,000

Re: dhcp issue: cannot obtain ip on wireless networks

Sarai:

Perhaps the reason for the difficulty is related to my experience with setting up wicd for wired static dsl.

The data for such a setup consists of IP,netmask,gateway and dns servers.
This data can be pre-setup and entered into /etc/wired-settings.conf.  This is all well and good and wicd recognizes the file thusly installed.

However, and this is the catch, it takes wicd 12 seconds to connect.

I suggest a similar delay is probably the reason for the variability in your wireless connection experience.

Just a thought.........
EDIT: As the system responds to the call for wicd, it first shuts wicd down and then restarts...perhaps this happens with the wireless system as well.......
EDIT #2:  Added info in that I invoked /etc/rc.d/wicd restart in order to install the static data place in /etc/wicd.wire-settings.conf.

The wicd system stops and restarts...then it scans for IP for 12 seconds before connecting.

The scan seems like an eternity.

Not having wireless for eth0, I do not know the wicd wireless-setting.conf performance with regard to scanning for IP.

Last edited by lilsirecho (2010-03-16 19:24:45)

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Sarai

Member

From: Alaska

Registered: 2010-02-20

Posts: 62

Re: dhcp issue: cannot obtain ip on wireless networks

Okay, I've got more info! I feel like I might be nearing an answer. I've been playing around with logs the last couple of days. Here are the errors from /var/log/errors.log for dhcpcd and dhclient, respectively.

Mar 19 13:30:27 sarai-laptop dhcpcd: dhcpcd not running
Mar 19 13:30:27 sarai-laptop dhcpcd: dhcpcd not running
Mar 19 13:30:27 sarai-laptop dhcpcd: dhcpcd not running
Mar 19 13:31:00 sarai-laptop dhcpcd: timed out

Mar 19 13:31:36 sarai-laptop dhclient: can't create /var/db/dhclient.leases: No such file or directory
Mar 19 13:31:36 sarai-laptop dhclient: can't create /var/db/dhclient.leases: No such file or directory
Mar 19 13:31:37 sarai-laptop dhclient: can't create /var/db/dhclient.leases: No such file or directory
Mar 19 13:31:40 sarai-laptop dhclient: can't create /var/db/dhclient.leases: No such file or directory
Mar 19 13:31:43 sarai-laptop dhclient: can't create /var/db/dhclient.leases: No such file or directory

I'm not sure exactly what to do for the dhcpcd error, other than the obvious (run dhcpcd, which I thought I was doing?! ). I checked and the directory /var/db doesn't exist, presumably that's what dhclient is whining about. Can I safely create it?

nitroguy

Member

Registered: 2009-10-16

Posts: 16

Re: dhcp issue: cannot obtain ip on wireless networks

I will have to do further testing tonight.  I doubt this is a dhcpcd bug and it has persisted annoyingly for weeks now.  For those of you looking to get to the bottom of it try the following commands to help you:

The following worked for me at the moment:

[myuser@myhost ~]$ sudo iwconfig wlan0 power off

(note, this disables power management, not actual on/off state from what I can tell)

For those completely lost you should at least learn what card type you have and what driver you are using:

[myuser@myhost ~]$ lspci | grep -i -E 'wireless|network'
00:19.0 Ethernet controller: Intel Corporation 82567LM Gigabit Network Connection (rev 03)
03:00.0 Network controller: Intel Corporation PRO/Wireless 5100 AGN [Shiloh] Network Connection

[myuser@myhost ~]$ lspci -vv -s 03:00.0
03:00.0 Network controller: Intel Corporation PRO/Wireless 5100 AGN [Shiloh] Network Connection
    Subsystem: Intel Corporation PRO/Wireless 5100AGN Network Connection
    Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx-
    Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
    Latency: 0, Cache Line Size: 64 bytes
    Interrupt: pin A routed to IRQ 30
    Region 0: Memory at f4300000 (64-bit, non-prefetchable) [size=8K]
    Capabilities: <access denied>
    Kernel driver in use: iwlagn
    Kernel modules: iwlagn


(NOW IF YOU REALLY WANT TO KNOW SOME LOW-LEVEL STUFF CHECK OUT phyX in /sys/...)
[myuser@myhost ieee80211]$ pwd && ls -l
/sys/class/ieee80211
lrwxrwxrwx 1 root root 0 Apr 12 11:09 phy0 -> ../../devices/pci0000:00/0000:00:1c.1/0000:03:00.0/ieee80211/phy0

Once you get your kernel driver you can try modprobe removing then adding again to see if it kickstarts it.  Also, knowing the exact name may lead you to other solutions specific to your card.

nitroguy

Member

Registered: 2009-10-16

Posts: 16

Re: dhcp issue: cannot obtain ip on wireless networks

It is not working anymore.  I am trying to debug from my AP side.  The logs never show DHCP DISCOVERS from my wlan0, only from my eth0.  DHCP works fine over the wired interface too.  No dhcp client succeeds on the wlan0 interface.

Could this be an issue with WPA_SUPPLICANT?  Time to disable encryption and figure it out ...

Sarai

Member

From: Alaska

Registered: 2010-02-20

Posts: 62

Re: dhcp issue: cannot obtain ip on wireless networks

It is not working anymore.  I am trying to debug from my AP side.  The logs never show DHCP DISCOVERS from my wlan0, only from my eth0.  DHCP works fine over the wired interface too.  No dhcp client succeeds on the wlan0 interface.

Could this be an issue with WPA_SUPPLICANT?  Time to disable encryption and figure it out ...

Possibly,  if you're having the same problem as me. Right now, I don't use any wireless networks that are encrypted and I haven't had this problem in weeks. My home one is restricted by MAC, which I know is bad but when I try to set any encryption at all it fails to get an IP. I've even assigned a static ip for my computer in the router, however when I try to set that static IP in wicd it whines about needing a DNS server even when I have it set to dynamic dns.
However, this is even a problem for WEP encryption so perhaps not the WPA supplicant specifically but a more general encryption problem? When I go home later I'll try using WPA to see if I can get an IP.

nitroguy

Member

Registered: 2009-10-16

Posts: 16

Re: dhcp issue: cannot obtain ip on wireless networks

Yes, this works fine without encryption.  Now to figure out why WPA2 messes up my life.

Sarai

Member

From: Alaska

Registered: 2010-02-20

Posts: 62

Re: dhcp issue: cannot obtain ip on wireless networks

Now to figure out why WPA2 messes up my life.

Does it need a reason? ^^

Try using WEP encryption, for a test.

Last edited by Sarai (2010-04-13 03:50:25)

shemz

Member

Registered: 2010-04-23

Posts: 135

Re: dhcp issue: cannot obtain ip on wireless networks

Any solution to this yet ? I have a similar problem while using NM. It connects well on wlan interface while using WPA2 Personal security, but times out with WPA2 Enterprise.

fizk-jnk

Member

Registered: 2010-09-03

Posts: 22

Re: dhcp issue: cannot obtain ip on wireless networks

Hello, sorry to revive an old thread, but I have the same issue... Is there any solution ?

In my case wicd connects to WPA2 just fine. However I can not connect to any open networks

I also have the entries "localhost dhcpcd[5548]: dhcpcd not running" in /var/log/errors.log....

EDIT : I found a solution. So for anyone having similar issues :

open the dhcpcd config : /etc/dhcpcd.conf  and add the following line to the end of the file:

waitip

According to the man page for dhcpcd.conf, it causes the dhcpcd to wait for address to be assigned before forking to background.

Cheers

Last edited by fizk-jnk (2011-01-20 00:50:31)