LPC1788+Uclinux DHCP not working

[lpcware]

Content originally posted in LPCWare by nohabviktor on Wed Dec 10 05:29:51 MST 2014
Hi!

I have a custom board with LPC1788, 32Mbyte SDRAM, 128 Mbyte Nand flash, on 108Mhz.
I download the emcraft uclinux and networking project.

The poroblem is the busybox udhcpc command:

init started: BusyBox v1.17.0 (2014-12-05 16:25:33 CET)                        
~ # ifconfig                                                                   
~ # udhcpc -f -i eth0                                                          
udhcpc (v1.17.0) started                                                       
Setting IP address 0.0.0.0 on eth0                                             
Sending discover 0...                                                          
Sending discover 0...                                                          
Sending select for 192.168.0.27...                                             
Received DHCP NAK                                                              
Sending discover 0...                                                          
Sending select for 192.168.0.27...                                             
Received DHCP NAK                                                              
Sending discover 0...                                                          
Sending select for 192.168.0.27...                                             
Received DHCP NAK                                                              
^C                                                                             
~ # ifconfig                                                                   
eth0      Link encap:Ethernet  HWaddr C0:B1:3C:88:88:84                        
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1                   
          RX packets:37 errors:0 dropped:0 overruns:0 frame:0                  
          TX packets:7 errors:0 dropped:0 overruns:0 carrier:0                 
          collisions:0 txqueuelen:1000                                         
          RX bytes:7432 (7.2 KiB)  TX bytes:2278 (2.2 KiB)                     
          Interrupt:28 Base address:0x4000                                     
                                                                               
~ #   

The u-boot is not send bootargs networking option.
udhcpc is always received NAK

this is the default script:

#!/bin/sh
# udhcpc script edited by Tim Riker <Tim@Rikers.org>

RESOLV_CONF="/etc/resolv.conf"

[ -n "$1" ] || { echo "Error: should be called from udhcpc"; exit 1; }

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

case "$1" in
deconfig)
echo "Setting IP address 0.0.0.0 on $interface"
ifconfig $interface 0.0.0.0
;;

renew|bound)
echo "Setting IP address $ip on $interface"
ifconfig $interface $ip $NETMASK $BROADCAST

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
echo "Adding router $i"
route add default gw $i dev $interface
done
fi

echo "Recreating $RESOLV_CONF"
echo -n > $RESOLV_CONF-$$
[ -n "$domain" ] && echo "search $domain" >> $RESOLV_CONF-$$
for i in $dns ; do
echo " Adding DNS server $i"
echo "nameserver $i" >> $RESOLV_CONF-$$
done
mv $RESOLV_CONF-$$ $RESOLV_CONF
;;
esac

exit 0





The 192.168.0.27 is correct ip address from my router, but why received nak?
Why not work the udhcpc, this is a default project I not modify, I don't understand.