命令如下，ESSID和key都配置了，但是使用dhcp就是无法拿到IP地址,顺便问一下怎么配置IP地址，我指手动指定一个

ECHO-BK:~# iwconfig eth1 essid echo-home key s:123456FFAC

ECHO-BK:~# iwconfig eth1
eth1 IEEE 802.11b/g ESSID:"echo-home" Nickname:"Broadcom 4311"
Mode:Managed Access Point: Invalid
RTS thrff Fragment thrff
Encryption key:3132-3334-3536-4646-4143-0000-00 Security modepen
Link Quality=0/100 Signal level=-256 dBm Noise level=-256 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

ECHO-BK:~# dhclient eth1
Internet Systems Consortium DHCP Client V3.0.4
Copyright 2004-2006 Internet Systems Consortium.
All rights reserved.
For info, please visit http://www.isc.org/sw/dhcp/

SIOCSIFFLAGS: No such file or directory
SIOCSIFFLAGS: No such file or directory
Listening on LPF/eth1/00:1a:73:07:3d:e6
Sending on LPF/eth1/00:1a:73:07:3d:e6
Sending on Socket/fallback
DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 6
send_packet: Network is down
receive_packet failed on eth1: Network is down
DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 7
send_packet: Network is down