Hello everyone!
I've switched to OPNsense after nearly 10 years of using a now old Synology RT1900ac and I've been honestly enjoying it all. Having tailscale integrated in the router is truly amazing but there's just one thing I would want to know if is possible. My current local LAN subnet is 192.168.1.0/24, I have a bunch of devices on it and I don't really plan on moving from it yet. The tailscale network I am in thankfully doesn't have any multiple 192.168.1.0/24 subnet conflicts, but the networks I connect from are using the 192.168.1.0/24 subnet locally as well. I mostly mitigated it by switching the other networks to 192.168.2.0/24, but I was actually wondering if there would be any possible idea to like... duplicate or mirror the subnet?
Let's say it like this.
I get to keep 192.168.1.0/24 locally for all the devices on the LAN.
I make a new 10.5.1.0/24 subnet that would be "hidden" or just virtual or basically transparent to interfaces (?)
Tailscale would be switched to advertise 10.5.1.0/24 instead of 192.168.1.0/24
All devices would be mirrored? (eg. LAN 192.168.1.3 <-> 10.5.1.3 Tailscale both ways)
I hope I can manage to describe the whole idea properly, I feel like I am dumb at this point because I've been trying to look for this over the internet but to no avail.
I did try some stuff with one to one NAT or virtual IPs but I am genuinely lost in all of this, making it worse that I lack proper networking knowledge as well.
EDIT: ofc that after sending a post I did manage to find this blogpost: https://jrs-s.net/2020/01/19/static-routing-through-vpn-servers-in-opnsense/
it got me further because I can indeed ping devices but still not access any ports even though the firewall live log shows them as passed.
EDIT2: managed to get it to work! can do a writeup if anyone wants