Understanding udhcpc: I'm missing something??

[Theliel]

Hardware: RT-AC656U
Firmware: Asus Merlin 378.55

Hi all.

I've been playing around with routes, interfaces and DHCP on my router, but I can't get DHCP working correctly.

I'd created a VLAN associated and tagged with WAN and CPU port through robocfg and got up with vconfig and ifconfig:

robocfg vlan 8 ports "4t 5t"
vconfig add eth0 8
ifconfig vlan8 up

All working fine.

Now, I want assing a DHCP addr to my new interface (no problem on server side), so I attempt with a simple udhcpc:

udhcpc -i vlan8
udhcpc (v1.20.2) started
Sending discover...
Sending select for 10.5.21.187...
Lease of 10.5.21.187 obtained, lease time 43200

Lease is received correctly, but is not assigned to my iface after all, my iface is not configured with the lease. I can make my iface working fine setting it manually (addr/mask with ifconfig) but i don't accomplishment this with udhcpc.

I'm missing something??
thank in advanced

 

[Teymur]

I have the same issuie in 2020. Did you fix your issue?

 

[bengalih]

I know this is old post, but found while searching for something else. My understanding is that udhcpc is, by itself only going to handle the communication with the DHCP server. By itself it does not actually configure the interfaces with the info that is returned.
For that, you need to use -s argument to call a script which you will pass the received information into.

You can read here:

https://udhcp.busybox.net/README.udhcpc

One example shown in a certain configuration on my box was:
/sbin/udhcpc -i eth0 -p /var/run/udhcpc0.pid -s /tmp/udhcpc -O33 -O249

I can't give you a lot of implementation detail, but this is where to start.