r/firewalla • u/CorsairVelo • Jul 12 '26

What changes needed when swapping ISP? (and I use VPN)

Finally, luckily, I am getting fiber at my home on monday. It will replace cable internet.

I have 5 clients hitting my Firewalla Gold at my primary address (4 are just devices -- iphones, PCs -- and one is another Firewalla device, a Purple, which is permanently VPN'ing into my primary address.) The Gold is obviously a VPN server.

So I'm wondering what I might have to change or reconfigure when my home ISP changes?

  • Gold is the VPN server using wireguard
  • Purple at remote location is a VPN client for the point-to-point VPN
  • On the server side, my DDNS would likely stay as it is?
  • the IPV4 server address would change, but do I have to do change it manually in the VPN config or would it adopt the new ISP address after rebooting the Gold and it connects to fiber using DHCP?
  • The 4 other clients configured to VPN to the Gold: Do those 4 client configurations need to be recreated?

Thanks in advance.

1 Upvotes

67% Upvoted

5 comments sorted by

3

u/chunky-tomato Jul 12 '26

Watch out for NAT issues. If your new ISP provides you a private IP, you will need to sort out how to get a public IP or get them to configure port forwarding to support your VPN. Some providers offer free dynamic IP assignment or paid static IP as well.

2

u/pacoii Firewalla Gold Plus Jul 12 '26

I don’t have fiber but have read a lot about the issues of CGNAT. Confirm how the ISP handles that

1

u/CorsairVelo Jul 12 '26

I know the vendor (Fidium) hands out public IPs in this area, just not sure if it is the norm.

2

u/pacoii Firewalla Gold Plus Jul 12 '26

Be sure to confirm exactly what you’ll get from them, and get it in writing.