Check DHCP Option content

Question

Is it possible DHCP client check the contents of an option ?

I need provisioning a Linux server with DHCP option 140 (option-140).

But the server behaves as if the DHCP did not contain the information.

In the file /var/lib/dhcp/dhclient.eth0.leases

I do not see advanced DHCP options (option-140, option-141, option-142).

How can I manually request the DHCP server to give me the contents of an option (to control the content)?

Solution

1. Fire up tcpdump or tshark on eth0... look for all UDP packets and make your sniffer give verbose output (see manpage)
2. sudo dhclient -r
3. sudo dhclient