Like a DMZ a VPN is a security concept, it is not a protocol (like SSH) nor a certain software package, There are multiple software packages available to set up a VPN between two or more hosts. They all use the Client-Server concept and usually are incompatible with one another. Have look at the OSI model and make yourself aware that the encryption can be applied at different layers of the
Linux StrongSwan Cilent # ipsec.conf - strongSwan IPsec configuration file # basic configuration config setup # strictcrlpolicy=yes # uniqueids = no # Add connections here. # Sample VPN connections #conn sample-self-signed # leftsubnet=10.1.0.0/16 # leftcert=selfCert.der linux - Which ports for IPSEC/LT2P? - Server Fault 2020-6-11 · Ipsec needs UDP port 500 + ip protocol 50 and 51 - but you can use NAt-T instead, which needs UDP port 4500. On the other hand L2TP uses udp port 1701. If you trying to pass ipsec traffic through a "regular" Wi-Fi router and there is no such option as IPSec pass-through, I recommend opening port 500 and 4500. At least that is how it works on mine.
UniFi - USG/UDM VPN: How to Configure Site-to-Site VPN
OpenWrt Project: VPN Overview
2015-10-21 · And this backs to the incompatibility of IPSec passthrough with the new feature “NAT-T” which is supported now on the routers internal VPN server. The Vigor2820 NAT-T support allows remote VPN clients that are behind a NAT router to more easily connect via VPN and let VPN traffic to passthrough the router.
Configuring IP Passthrough Business customers sometimes state that they need DSL/Broadband CPE that can be configured or placed into a Bridged Mode where they are putting other CPE behind the DSL/Broadband CPE. Many times these customers can be better served with a configuration known as IP Passthrough. IPsec can protect data flows between a pair of hosts (host-to-host), between a pair of security gateways (network-to-network), or between a security gateway and a host (network-to-host). IPsec uses cryptographic security services to protect communications over Internet Protocol (IP) networks. It supports network-level peer authentication, data do I need to leave the L2TP, PPTP and IPSec passthrough set on my home router? - the default value is set for the 3 of them. Thanks p.s. just looking for quick answers.