[Watford] Raspberry Pi Wifi set-up?

[Jim Ford]

I'm trying to get wifi set up on my raspberry pi.

I'm running the raspberry 'headless' with a network cable, and a ssh 
using 'putty'.

The USB dongle driver works ok as indicated by lsusb and lsmod, and also 
the wlan0 interface comes up, as shown below. Also iwlist wlan0 scan 
shows my router (and others):

eth0      Link encap:Ethernet  HWaddr b8:27:eb:d9:33:aa
           inet addr:192.168.1.128  Bcast:192.168.1.255  Mask:255.255.255.0
           inet6 addr: fe80::ba27:ebff:fed9:33aa/64 Scope:Link
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:1039 errors:0 dropped:0 overruns:0 frame:0
           TX packets:1452 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:63698 (62.2 KiB)  TX bytes:190755 (186.2 KiB)

lo        Link encap:Local Loopback
           inet addr:127.0.0.1  Mask:255.0.0.0
           inet6 addr: ::1/128 Scope:Host
           UP LOOPBACK RUNNING  MTU:16436  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

wlan0     Link encap:Ethernet  HWaddr 48:02:2a:eb:ae:b2
           UP BROADCAST MULTICAST  MTU:1500  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

The problem appears to be that although I'm getting an IP address from 
my router for eth0, I'm not getting one for the wlan0 interface.

I'm wondering whether the eth0 interface somehow inhibits the wlan0 from 
getting an IP

I'd be grateful for any pointers to where the problem might lie, please.


BTW. I only discovered the Watford Linux Group this evening. I'm a 
Watford resident and have tinkered with Linux for some years, though I'm 
no expert. I hope to get to the 'Sportsman' this Thursday.

Jim