Client L2TP/IPsec VPN behind OPNsense router to Work VPN not working

[roarst]

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.

[errored out]

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.