My WAN router, a TP-LINK Archer C2 doesn't have a local DNS server for DHCP'd clients so I was looking for another solution. I found the Dual DHCP DNS Server for Windows and installed it on the LAN server. It seems to work fine when I'm inspecting the network traffic.
When a client wants an IP address, it gets a DHCP response with an IP address, DNS and gateway addresses. The server's address is 192.168.18.2 and the TP-LINK router has 192.168.18.1. The router option (3) is correctly set to 192.168.18.1.
But neither a Samsung Android phone nor the Kyocera printer regard the default dateway value. They happily accept their own IP address but state they have no gateway and cannot connect to the internet.
Both a simple tool named dhcptest.exe and Wireshark parse the DHCP response and list the router IP address as expected.
What's going on here? Why does every client ignore the gateway address from the one server when they accept the gateway address from the TP-LINK DHCP server? It's driving me mad and wanting to throw the TP-LINK device out of the window and get a decent router that can handle LAN hostnames properly.