Join 2 networks and DNS entries
 

There is a network 172.16.84.0/24. This network restricts access to Internet via proxy and have urls *.company.com. Let's call this NET_A.
There is a different network 192.168.1.0/24 that it does dhcp and no restriction to internet through a DSL router. Lets call this NET_B
I would like a small portion of devices to have unrestricted access to the Internet and be able to access the company's network (*.company.com).

I thought two solutions, but i am stuck in the implementation for both of them:

Solution 1
To have a local dns server that has entries for the *.company.com. The IP of the DNS server will be on the DSL router.


Solution 2
Use an additional router with 3 ethernet ports.
-eth0: NET_A
-eth1: NET_B. Default gateway will be here.
-eth2: NET_C, will be the the new LAN for the devices.


i would like to ask for some help please.

After looking at your question all day, I can think of one simple solution that I know can work (because I used to do something similar) - but what I am thinking of would require you to change the local subnets from 172.16.84.0/24 and 192.168.1.0/24 to somethings else. Do you have the authority to make such a change?

You can create two VLAN interfaces over NET_A. One VLAN support DNS and another not.