Road Warriors are remote users who need secure access to the company’s infrastructure. IPsec Mobile Clients offer a solution that is easy to setup and comptabile with most current devices.
With this guide we will show you how to configure the server side on OPNsense with the different authentication methods e.g.
- Mutual-PSK + XAuth
- Mutual-RSA + XAuth
For the sample we will use a private ip for our WAN connection. This requires us to disable the default block rule on WAN to allow private traffic. To do so, go toand uncheck “Block private networks”. (Don’t forget to save and apply)
All configuration examples are based on the following setup, please read this carefully as all guides depend on it.
Company Network with Remote Client
To allow IPsec Tunnel Connections, the following should be allowed on WAN.
- Protocol ESP
- UDP Traffic on Port 500 (ISAKMP)
- UDP Traffic on Port 4500 (NAT-T)
To allow traffic passing to your LAN subnet you need to add a rule to the IPsec interface.
In the next table you can see the existing VPN authentication mechanisms and which client operating systems support it, with links to their configurations. For Linux testing was done with Ubuntu 18.4 Desktop and network-manager-strongswan and libcharon-extra-plugins installed. As Andoid does not support IKEv2 yet we added notes for combinations with strongSwan app installed to have a broader compatibility for all systems. Mutual RSA and PSK without XAuth requires L2TP, since this legacy technology is very error prone we will not cover it here.