I am new to OPNsense (just started using it today). I just switched from a Netgear Nighthawk X6 (R8000) to OPNsense 20.7. Everything seems like a smooth switch except for my work L2TP/IPsec VPN.
I'm using a Windows 10 Pro 2004 client with the native VPN client. The VPN worked before I switched from the Netgear router to the OPNsense router. I have not made any changes on the client side. When I try to connect, it just hangs for awhile and then never moves past 'connecting'.
I'm getting the RasClient error in the event log: The error code returned on failure is 809.
In some digging it appears the firewall on OPNsense is blocking the necessary UDP traffic for the VPN to work: L2TP over IPSec
To allow Internet Key Exchange (IKE), open UDP 500.
To allow IPSec Network Address Translation (NAT-T) open UDP 4500.
To allow L2TP traffic, open UDP 1701.
I'm not sure how to achieve this, and I really don't want to do something wrong that would allow any traffic into my home network over these ports. Any help on this matter would be appreciated.
Have you tried reading the documentation?
https://docs.opnsense.org/manual/firewall.html
Also, what changes have you made? I'm guessing you have specified some interface rules.