How to create a separate local network, with Internet access, within a network with restrictions?

Question

Computer networks

There is a small business. There is a router from the provider, only one port is available, which goes to an unmanaged switch. The network is static. It has a mask - 255.255.255.128 and a gateway 10.128.217.129, dns - 10.128.1.23.
I would like a separate local network with dhcp or at least dhcp for an existing network. There is a second router with dhcp server function.

What needs to be done to make everything work?

Answer 1

Set your router as a gateway between the internal network and the provider. You configure NAT, DHCP, port forwarding for services that should be available from the outside (if any) on it.
If the router is advanced, like Mikrotik, you can also raise DNS and much more.

Answer 2

well, if it is permissible - remove the provider's router and put your own, on which you already raise the necessary
one; if not, stick your router into this "one" port of the provider's router, and the switch is already in your router