A VPN is essentially a way to securely bridge two networks (particularly in the context of your question - often referred to as "LAN-to-LAN" or "site to site" VPN. A firewall is a device which manages packets passing thought it depending on various criteria. The aim is usually to opacify services "behind" the firewall.
It's a 'cheap' TP-link router that only support client-site vpn but not site-site. For now we configured it to establish a client-site VPN so computers behind this router can access resources in main office. But from main office we can't connect /access computers that are behind this 'soho' router. Perhaps so, a VPN connected to your router is a much easier way to use VPN across all platforms. Since you will always be connected to VPN through your router, you will not have to log in every time you use a different device to use the web. Read: How to setup a secure wireless router. Disadvantages of connecting your VPN to your router It is A VPN server should always have a public IP address. It should not be operated behind a NAT router. If it must be, put the VPN server into the WAG LAN 192.168.1.0/24. Another alternative could be to setup the WAG as simple bridge (i.e. a simple modem) and configure the firewall your internet connection doing NAT. Often web server access to remote devices behind a firewall is needed (Wifi router, smart home). This is how you can solve this securely. Find this and other hardware projects on Hackster.io.
Troubleshooting VPN passthrough for home routers | Answer
Using a SonicWall firewall behind the Comcast Router However this is the first question. The router currently has the WAN IP at 50.73.107.102 and the Gateway at 24.13.50.1. The static IP we were assigned is 50.73.107.101 with the Gateway at .102. This seems odd this the new Gateway is the current WAN IP? Our goal is to put into place a Sonicwall firewall so that we can accept secure VPN connections. Installation behind firewall (Ipfire) - installation Jul 08, 2019
[SOLVED] VPN Setup behind Firewall - Best Practices
However this is the first question. The router currently has the WAN IP at 50.73.107.102 and the Gateway at 24.13.50.1. The static IP we were assigned is 50.73.107.101 with the Gateway at .102. This seems odd this the new Gateway is the current WAN IP? Our goal is to put into place a Sonicwall firewall so that we can accept secure VPN connections.