How to distribute the Internet to a local network without a proxy?

Question

local server

There is a local area network on 50+ computers.
Routing is implemented on win server 2008.
The problem is that it is necessary to carry out proxy authorization on each of the computers in the local network in order to have Internet access, this is very inconvenient and because of this a large number of difficulties arise.
How to rebuild the routing so that the local network is already automated at the server station? (It is advisable not to resort to any additional software)