1．在內(nèi)核中添加以下選項(xiàng)：
Networking--->

• Networking support
  Networking options--->
  Packet socket //添加.配置CONFIG_PACKET
  [ * ] IP: DHCP support //添加
  [ * ] Network packet filtering (replaces ipchains)---> //添加，后面子選項(xiàng)可不選，配置CONFIG_NETFILTER
  說明：若沒選 Packet socket, [ * ] Network packet filtering (replaces ipchains)--->選項(xiàng)，在執(zhí)行udhcpc命令時出現(xiàn)如下錯誤：
  ~ # udhcpc
  udhcpc (v0.9.9-pre) started
  udhcpc[208]: udhcpc (v0.9.9-pre) started
  
  FATAL: couldnt listen on socket, Address family not supported by protocol
  udhcpc[208]: FATAL: couldnt listen on socket, Address family not supported by protocol
  2．Busybox中添加以下選項(xiàng)：
  Networking Utilities--->
  udhcp Server/Client--->
  [] udhcp Server (udhcpd) //在此不作服務(wù)端，故不選。生成udhcpd命令
  
• udhcp Client (udhcpc) //生成udhcpc命令
  [ ] Lease display utility (dumpleases)
  [ ] Log udhcp messages to syslog (instead of stdout)
  [ ] Compile udhcp with noisy debugging messages
  若busybox沒編譯相應(yīng)選項(xiàng)，也可從網(wǎng)上下載相應(yīng)文件，用arm-linux交叉編譯得到udhcpd,udhcpc命令copy到usr/sbin下就可以了。
  我從 網(wǎng)上下的udhcp_0.9.8cvs20050303.orig.tar.gz文件
  解壓后修改Makefile文件
  在19行添加CROSS_COMPILE=arm-linux-
  注釋12行的COMBINED_BINARY=1，否則不生成udhcpc命令。
  3．建相關(guān)配置文件
  從busybox的examples/udhcp/下copysimple.script文件到開發(fā)板/usr/share/udhcpc/下，并重命名為default.script，udhcp_0.9.8cvs20050303.orig.tar.gz中也有這樣的文件。
  [root@localhost root]# vi usr/share/udhcpc/default.script
  #!/bin/sh
  
  # udhcpc script edited by Tim Riker
  
  [ -z "$1" ] && echo "Error: should be called from udhcpc" && exit 1
  
  RESOLV_CONF="/etc/resolv.conf"
  [ -n "$broadcast" ] && BROADCAST="broadcast $broadcast"
  [ -n "$subnet" ] && NETMASK="netmask $subnet"
  
  case "$1" in
  deconfig)
  /sbin/ifconfig $interface 0.0.0.0
  ;;
  
  renew|bound)
  /sbin/ifconfig $interface $ip $BROADCAST $NETMASK
  
  if [ -n "$router" ] ; then
  echo "deleting routers"
  while route del default gw 0.0.0.0 dev $interface ; do
  :
  done
  for i in $router ; do
  route add default gw $i dev $interface
  done
  fi
  
  echo -n > $RESOLV_CONF
  [ -n "$domain" ] && echo search $domain >> $RESOLV_CONF
  for i in $dns ; do
  echo adding dns $i
  echo nameserver $i >> $RESOLV_CONF
  done
  ;;
  esac
  
  exit 0
  
  4．重啟開發(fā)板，執(zhí)行udhcpc就可自動獲取IP地址了，以下是執(zhí)行udhcpc的輸出信息：
  
  ~ # udhcpc
  udhcpc (v0.9.9-pre) started
  udhcpc[228]: udhcpc (v0.9.9-pre) started
  
  Sending discover...
  udhcpc[228]: Sending discover...
  
  Sending select for 192.168.1.109...
  udhcpc[228]: Sending select for 192.168.1.109...
  
  Lease of 192.168.1.109 obtained, lease time 86400
  udhcpc[228]: Lease of 192.168.1.109 obtained, lease time 86400
  
  deleting routers
  route: SIOC[ADD|DEL]RT: No such process
  adding dns 192.168.0.1
  ~ # ping www.baidu.com
  PING www.a.shifen.com (220.181.38.4): 56 data bytes
  64 bytes from 220.181.38.4: icmp_seq=0 ttl=52 time=1219.0 ms
  [1] + Stopped ping www.baidu.com
  
  5．如果是雙網(wǎng)卡必須用參數(shù)指明
  例：udhcpc-ieth1