tried to search for something similar, but i failed, so i’m posting new thread.
Main problem: I can ping my “router” from client PC by IP, but unable to ping anything else on the internet. Firewall is OFF, for testing reasons…
If your client got an IP address and a gateway from the “router” then DHCP is working correctly and being able to ping an external host is a different problem. You can check if the client got a DHCP lease with “ipconfig /all” on Windows and “ifconfig”, “route -n” and “cat /etc/resolv.conf” on Linux.
Sounds like you want IP forwarding. For this you have to configure the router for forwarding and also the firewall rules. There should be a Wiki document on configuring openSUSE as a router. I have a separate gateway/router/firewall so I can’t give you much guidance on configuring openSUSE as a gateway/router.