arm linux开发板自动配置IP地址

配置内核：

[*] Networking support --->
Networking options --->
<*> Packet socket
<*> Unix domain sockets
[*] TCP/IP networking
[*] IP: kernel level autoconfiguration
[*] IP: DHCP support
[*] Network packet filtering framework (Netfilter) --->

配置busybox:

Networking Utilities --->
[*] udhcp client (udhcpc)

3.建立配置文件：

从busybox的examples/udhcp/下copy simple.script文件到开发板/usr/share/udhcpc/下，并重命名为default.script

4. 测试：

在命令台执行udhcpc，注意：必须确保局域网内存在DHCP服务器，否则udhcp执行失败。

在easy2440上面执行结果如下：

[root@liebao:/usr/share/udhcpc]#udhcpc
udhcpc: started, v1.28.1
Setting IP address 0.0.0.0 on eth0
udhcpc: sending discover
udhcpc: sending select for 172.16.21.230
udhcpc: lease of 172.16.21.230 obtained, lease time 86400
Setting IP address 172.16.21.230 on eth0
Deleting routers
route: SIOCDELRT: No such process
Adding router 172.16.21.254
Recreating /etc/resolv.conf
Adding DNS server 202.106.0.20

ifconfig查看：

[root@liebao:/usr/share/udhcpc]#ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0A:2D:A6:55:A2
inet addr:172.16.21.230  Bcast:172.16.21.255  Mask:255.255.255.0
inet6 addr: fe80::20a:2dff:fea6:55a2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:231 errors:0 dropped:35 overruns:0 frame:0
TX packets:82 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:31511 (30.7 KiB)  TX bytes:9144 (8.9 KiB)
Interrupt:106 Base address:0xc000

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:65536  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:1
RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

ping百度测试一下：

[root@liebao:/usr/share/udhcpc]#ping www.baidu.com -c4
PING www.baidu.com (61.135.169.121): 56 data bytes
64 bytes from 61.135.169.121: seq=0 ttl=55 time=2.871 ms
64 bytes from 61.135.169.121: seq=1 ttl=55 time=2.593 ms
64 bytes from 61.135.169.121: seq=2 ttl=55 time=2.416 ms
64 bytes from 61.135.169.121: seq=3 ttl=55 time=2.447 ms

--- www.baidu.com ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 2.416/2.581/2.871 ms

可以ping通说明自动配置成功！

5. 修改系统初始化配置文件，让开发板开机后自动获取IP地址：

修改/etc/init.d/rcS文件在适当位置添加命令: /sbin/udhcpc &