DHCP Config

How to configure DHCP client of a embedded Linux device running a busy box?

1. Make sure you have udhcpc installed.
2. Find the configuration file at busybox-1.13.3 (this is the version of udhcp on my platform) /examples/udhcp/sample.renew.
3. Copy a configuration file to /usr/share/udhcpc/default.script, and change the RESOLV_CONF path to /etc/resolv.conf the content of the file looks like below:

#!/bin/sh
# Sample udhcpc bound script

RESOLV_CONF="/etc/resolv.conf"

[ -n "$broadcast" ] && BROADCAST="broadcast $broadcast"
[ -n "$subnet" ] && NETMASK="netmask $subnet"

/sbin/ifconfig $interface $ip $BROADCAST $NETMASK

if [ -n "$router" ]
then
    echo "deleting routers"
    while /sbin/route del default gw 0.0.0.0 dev $interface
    do :
    done

    metric=0
    for i in $router
    do
        /sbin/route add default gw $i dev $interface metric $((metric++))
    done
fi

echo -n > $RESOLV_CONF
[ -n "$domain" ] && echo domain $domain >> $RESOLV_CONF
for i in $dns
do
    echo adding dns $i
    echo nameserver $i >> $RESOLV_CONF
done

4. To get the new ip
#udhcpc eth0

reference:
http://tinyurl.com/3pd45s8