# No DHCP request response when running Linux [SOLVED]

## XelKarin

I'm afraid this may be a bit off topic as it's a general issue that I'm having, but seeing as I run Gentoo I decided I would ask here.  There's a coffee shop I frequent that has recently come under new ownership.  They've changed their Wifi setup and now, when I'm running Linux, I get no response to my DHCP requests.  I'm able to connect fine under Windows, though.  I was wondering if it's possible to configure DHCP to only accept requests from certain operating systems and if that's what they may have done there?Last edited by XelKarin on Thu Jun 14, 2012 10:52 pm; edited 1 time in total

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## khayyam

XelKarin ...

well, no, and any out of the box wireless router wouldn't have such a 'feature', MAC address filtering perhaps, but not OS. There is probably some simpler reason behind it, but your not really giving us much to work with, like how you connect, what DHCP client you use, and any logs that show the DHCP negociation failing. Infact, what leads you to think its DHCP?

The more/better information you can provide us, the easier it'll be to figure out whats going on ... and hopefully resolve it.

best ... khay

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## XelKarin

Well, I'm running wpa_supplicant and dhcpcd.  wpa_supplicant connects to the wireless network fine, but dhcpcd just doesn't receive an address.  Here's my configuration and log snippets.

/etc/conf.d/net

```
config_eth0="dhcp"

dhcpcd_eth0="-C ntp.conf -t 10 -q"

modules_wlan0="wpa_supplicant"

wpa_supplicant_wlan0="-Dwext"

config_wlan0="dhcp"

dhcpcd_wlan0="-C ntp.conf -t 10 -q"

iwconfig_wlan0="mode managed"
```

/etc/wpa_supplicant/wpa_supplicant.conf

```
ctrl_interface=/var/run/wpa_supplicant

eapol_version=1

ap_scan=1

fast_reauth=1

network={

   ssid="friendscafe"

   key_mgmt=NONE

   wep_key0="secret"

}
```

wlan0

```
wlan0     IEEE 802.11abgn  ESSID:"friendscafe"  

          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:7F:28:F8:11:7D   

          Bit Rate=1 Mb/s   Tx-Power=15 dBm   

          Retry  long limit:7   RTS thr:off   Fragment thr:off

          Encryption key:off

          Power Management:off

          Link Quality=70/70  Signal level=-39 dBm  

          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0

          Tx excessive retries:0  Invalid misc:150   Missed beacon:0
```

dhcpcd log

```
dhcpcd[3810]: version 5.2.12 starting

dhcpcd[3810]: wlan0: using hwaddr 00:21:6a:ac:9f:6e

dhcpcd[3810]: wlan0: executing `/lib64/dhcpcd/dhcpcd-run-hooks', reason PREINIT

dhcpcd[3810]: wlan0: executing `/lib64/dhcpcd/dhcpcd-run-hooks', reason CARRIER

dhcpcd[3810]: wlan0: broadcasting for a lease

dhcpcd[3810]: wlan0: sending DISCOVER (xid 0x6b7a6538), next in 4.86 seconds

dhcpcd[3810]: wlan0: sending DISCOVER (xid 0x6b7a6538), next in 8.16 seconds

dhcpcd[3810]: wlan0: sending DISCOVER (xid 0x6b7a6538), next in 16.09 seconds

dhcpcd[3810]: wlan0: sending DISCOVER (xid 0x6b7a6538), next in 32.16 seconds

dhcpcd[3810]: timed out

dhcpcd[3810]: allowing 8 seconds for IPv4LL timeout

dhcpcd[3810]: wlan0: probing for an IPv4LL address

dhcpcd[3810]: wlan0: checking for 169.254.42.63

dhcpcd[3810]: wlan0: sending ARP probe (1 of 3), next in 1.32 seconds

dhcpcd[3810]: wlan0: sending ARP probe (2 of 3), next in 1.09 seconds

dhcpcd[3810]: wlan0: sending ARP probe (3 of 3), next in 2.00 seconds

dhcpcd[3810]: wlan0: using IPv4LL address 169.254.42.63

dhcpcd[3810]: wlan0: adding IP address 169.254.42.63/16

dhcpcd[3810]: wlan0: adding route to 169.254.0.0/16

dhcpcd[3810]: wlan0: writing lease `/var/lib/dhcpcd/dhcpcd-wlan0.lease'

dhcpcd[3810]: wlan0: executing `/lib64/dhcpcd/dhcpcd-run-hooks', reason IPV4LL

dhcpcd[3810]: forking to background

dhcpcd[3810]: forked to background, child pid 3830
```

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## XelKarin

Ok, looking at wlan0, I'm seeing that the connection is not encrypted and all packets passing through are invalid.  I'm guessing I'm not properly authenticated.  So it seems I'm missing something in my wpa_supplicant configuration.  I tried my usual WPA configuration with this network and it didn't work.  This network apparently uses WEP and I'm at a bit of a loss configuring it.

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## khayyam

XelKarin ...

OK, well you should see something like the following if wpa_supplicant successfully negociates a connection ...

```
% awk '/wpa/{print}' /var/log/messages

Jun 10 15:27:34 hostname wpa_cli: interface wlan0 CONNECTED
```

As for configuring WEP:

```
network={

       ssid="friendscafe"

       scan_ssid=1

       key_mgmt=NONE

       wep_key0=secret

       wep_tx_keyidx=0

}
```

The "eapol_version=1" option I've never seen before, "eapol_flags=" yes, anyhow, none of the options you have set are strickly necessary, so perhaps comment them if you still have problems.

HTH & best ...

khay

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## cwr

If it will connect under Windows, it will connect under Linux; I'm suprised

they are using WEP, but you should be able to get the configuration and

the passphrase they are using by booting Windows and checking the

configuration there.

Will

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## XelKarin

Ok, so I thought the key they gave me was a password string (yes, it was a readable word), but on closer inspection I realized it was valid hexadecimal.  I removed the quotes from around wep_key0 and everything worked.

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## khayyam

ok ... good ... you should now mark this thread as '[SOLVED]'

BTW, I never quote 'psk=' or 'wep_key0=' as I've also had occasions when the key is thought to include the quotes. This can happen with WPA if the key is max length (63 chars), the last quote will be truncated and so the first included as part of the psk, and of course the authentication will fail. As the quotes are not required I see no reason to use them ...

best ... khay

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