My doubt is quite strange ..
On my Linux server a DHCP server application is waiting on the port number 547 for dhcp client messages.
Even though I am seeing messages from dhcp client on wireshark (running on my Linux server) .. dhcp server is not replying back.
Is there anyway to confirm the packet is actually processed by dhcp server or dropped in between by Linux ip stack ?
DHCP server is proprietary code so that I cant modify it to add more logs or check at recv function.
Just consider it as a generic question based on sockets rather than DHCP specific. My intrest is how can we know from an stats or other stuff that packet has been received in appropriate socket buffers.
You can do so by building the DHCP server with debugging symbols – your distribution maybe already has a *-dbg package ready for that. By attaching a debugger like gdb to the process, you may intercept messages and debug it to see where the problem is.
However, I’d first try to work with the usual possibilities, namely log-messages. Have you tried to activate Debug logging in your DHCP daemon yet?