docs(NET-1024): add docs for internet gateways

Author: Aceix

features.rst

@@ -43,6 +43,8 @@ Netmaker Professional is our advanced Netmaker offering for business use cases.
 
 - **Relays:** All traffic routing to and from in a network for a relayed machine will go through the relay machine.
 
+- **Internet Gateways:** These work similar to traditional VPNs, and can work with netclients (hosts in the mesh network) as well as with remote devices connected to the network via client configs.
+
 .. toctree::
    :maxdepth: 1
 

pro/index.rst

@@ -69,3 +69,11 @@ FailOvers
    :maxdepth: 2
 
    pro-failovers
+
+Internet Gateways
+-----------------------
+
+.. toctree::
+   :maxdepth: 2
+
+   internet-gateways

pro/internet-gateways.rst

@@ -0,0 +1,33 @@
+===================================
+Internet Gateways
+===================================
+
+Internet gateways is a Pro-only feature that allows hosts in a Netmaker mesh network to connect to the internet via a gateway. This brings the possibility of a traditional VPN to machines with netclient installed on them. Internet gateways can be configured from the Internet gateway tab.
+
+Only Linux hosts can be setup as internet gateways. Both Windows and Linux hosts can be connected to an internet gateway however. Remote clients can also be connected to internet gateways via a client config.
+
+This feature was introduced in v0.23.0 and is in beta (for this release).
+
+
+Usage
+======
+
+Create an internet gateway
+--------------------------
+
+1. Under a network, switch to the "Internet Gateways" tab
+2. Click on Create Gateway
+3. Select the desired Linux host to serve as the internet gateway (VPN server, in traditional parlance)
+4. Optionally choose the hosts you want to connect to the internet gateway
+5. Click on create
+
+**NOTE:** A host can only be connected to at most one internet gateway, regardless of the networks the host is in.
+
+
+FAQs and Known Issues
+=====================
+
+**Q: Why not Remote Access Gateway as an internet gateway.**
+
+A: Although possible, that serves a similar but different use case. Internet gateways allow not only remote clients, but also and peculiarly, hosts in the Netmaker mesh network to also connect to the internet via a gateway.
+This brings the possiblility of a traditional VPN to machines with netclient installed on them. This feature can be accessed from the Internet gateway tab.