vpn: added globalprotect entry

wiki/global_protect.md

@@ -0,0 +1,21 @@
+# Global Protect 
+
+[Global Protect](https://www.paloaltonetworks.de/resources/datasheets/globalprotect-datasheet) is a
+cross-platform [VPN](/wiki/vpn.md).
+
+## Installation
+
+The Global Protect client is available for [Windows](/wiki/windows.md), MacOS,
+[Linux](/wiki/linux.md), [Android](/wiki/android.md) aswell as iOs and iPadOS.
+On some Linux distributions the package is called `globalprotect-openconnect` but the corresponding
+command is called `gpclient` which can sometimes lead to confusion.
+
+## Usage 
+
+The usage of the Global Protect client is pretty simple.
+After starting the program the portal address has to be added and is followed by a login.
+Afterwards the client will connect.
+
+Global Protect is usually used by bigger companies and universities like the
+[University of Oldenburg](https://uol.de/it-services/services/campus-network) which wrote a proper
+installation and usage guide for all the operating systems that are supported.

wiki/vpn.md

@@ -15,4 +15,5 @@ This section lists various VPN implementations.
 - [OpenVPN](/wiki/openvpn.md) is probably the most well known VPN implementation.
 - [WireGuard](/wiki/wireguard.md) is a modern, fast and secure implementation of the VPN protocol.
   It is free and open-source.
-- Global Protect is a proprietary VPN that is mostly used by corporation and learning facilities.
+- [Global Protect](/wiki/global_protect.md) is a proprietary VPN that is mostly used by corporation
+  and learning facilities.