OPNsense Forum

English Forums => Virtual private networks => Topic started by: cidimir on December 09, 2025, 08:06:14 AM

Title: Routing OpenVPN Traffic through IPsec
Post by: cidimir on December 09, 2025, 08:06:14 AM
I have an ipsec VPN set up between Site A (192.168.168.0/24) and Site B (10.0.0.0/24).

Site A is behind a Sonicwall; Site B is behind OPNSense. They can ping, file share, RDP, etc. correctly.

I've configured OpenVPN on the OPNSense box (assigning users an IP in the range 10.10.10.0/24 upon successful connection.) OpenVPN users can successfully reach the Site B LAN network (10.0.0.0/24) no problem.

What I want is for them to also be able to reach the Site A network; to ping or RDP to 192.168.168.x and for that to successfully go through OpenVPN, through the ipsec tunnel, and respond back.

However, a traceroute OpenVPN -> Site A won't even go through the OpenVPN tunnel unless 192.168.168.0/24 is a local route on the OpenVPN instance.

My current ipsec config has two children:

Local         Remote
10.0.0.0/24      192.168.168.0/24
10.10.10.0/24           192.168.168.0/24

My OpenVPN instance has 10.0.0.0 and 192.168.168.0 as local networks for routing.

What am I missing? Any help would be appreciated.
Title: Re: Routing OpenVPN Traffic through IPsec
Post by: Monviech (Cedrik) on December 09, 2025, 08:16:08 AM
Does the IPsec tunnel have an SA open that allows the OpenVPN source network through, and the other side of the IPsec tunnel to return packets to that source?
Title: Re: Routing OpenVPN Traffic through IPsec
Post by: cidimir on December 09, 2025, 10:06:51 PM
It did, but what it didn't have was a SPD for the second child. For whatever reason, OPNSense only generated a source/dest pair for the first child, so I had to manually add a new pair for the second child and then associate them together with a reqid. It's functioning now.