Beginner Installing OPNSense to use as a router.

[meddyuk76]

Hey all, hope you are well.

Evening all - hope you are well?

I want to replace my BT Smart Hub ISP router with OPNsense.

I want to install OPNSense on a VM inside Proxmox and utilse a dual NIC. My plan is to utilise the Full Fibre and by pass and do away with the ISP Router. I then intend on purchasing a Unifi AP for the Wifi.

Its the first time attempting this and I will be managing the LAN/WIFI for the whole family.

Before I start this, is there anything I should be aware of/worried about/ensure that I do?

Is there any guides on how to do it properly, without bodging the family internet?

Cheers.

[Bob.Dig]

without bodging the family internet?

No.

Start with OPNsense as a second router only for your devices and see, how it goes.

[cookiemonster]

Before I start this, is there anything I should be aware of/worried about/ensure that I do?

Is there any guides on how to do it properly, without bodging the family internet?

The docs are a good place to start but they don't have this scenario. It's not an unreasonable one but is not described, so if you know your way around networks, it isn't too hard. But if you aren't, then you could have some networking behaviours that might seem "broken", or things might appear "not working".
Think of it this way, have you ever put a router behind another router and all was good? Then you're ready.
You haven't done that before, then you need to start reading. No, there is no recipe. Why? Because there are so many options and services in OPN that can be used, or not. Are you familiar with NAT? What about double NAT? Well, you are heading in Double NAT direction, with additional networking thrown in (Proxmox has its own networking stack).
I'm not trying to put you off. It'll be a good ride. Just be prepared for some new learning.
https://docs.opnsense.org/intro.html#reading-guide

[dseven]

TBF, the OP will only be heading in the double-NAT direction if they follow Bob.Dig's advice. It wasn't their stated intent. It may not be a bad idea, though, especially if they're learning Proxmox from scratch too, and there's a family depending on functional internet. I imagine there are tutorials (for a secondary firewall on Proxmox) out there...

[cookiemonster]

True. I'm pretty sure I saw one somewhere, maybe the network guy place.
Point being though, although double nat is not necessarily something that doesn't work i.e. it is best to avoid if possible but otherwise things work fine, there are so many threads here where the user plonks their new router with OPN behind their existing one "so to test and ready for switchover" but then so many "things don't work correctly", and not having done an even cursory read of the basics, that it is worth IMHO to write this note from the off.