Zerotier on Raspi as full tunnel VPN , a minor issue

I wanted to setup a full tunnel VPN at home on my Raspi, leveraging on Zerotier. To use when I’m travelling, a common request.

I used this guide. This and the zerotier atlassian guides are the best out there so far.

Under Zerotier ‘Managed Routes’, I added 0.0.0.0/0 via 192.168.ABC.DEF (this is the Zerotier IP address of the Raspi). This allows all traffic to be routed via the VPN, I think.

Tested it using a cellular connection on iphone and Zerotier (with Default turned on) and it works brilliantly.

Whatismyip shows my home IP. I could surf the web via the vpn tunnel. I can see and access my home LAN PC and router (all without Zerotier) as well as other PCs (connected via Zerotier).

Absolutely PERFECT!!!

But… then I tried another common scenario.

Say I’m at Mike’s home and connected to Mike’s wifi. I could no longer access my home router and PCs (those without Zerotier installed). I could still connect to my PCs with Zerotier installed though. Why is that??

I suspect the reason is because both my home network and Mike’s home network use the same default 192.168.1.xxx. So when I try to login to my home router at 192.1681.1, for example, it gets routed to Mike’s home router (also at 192.168.1.1) instead of my home router via Zerotier.

  1. Does this mean I MUST change my home network range to something else less common than 192.168.1.xxx in order to avoid this sort of conflict when I’m travelling since I don’t have control over Mike’s network? And if it clashes, then tough luck?
  2. If not, what can I do to make my home network (over Zerotier) take priority over the Mike’s network. Or even better, completely ignore Mike’s local network as if it doesn’t exist?

I’m a noob at networking so be gentle with instructions and suggestions, I’m not great with jargon or inner workings of IPtables and bridging.

You’re absolutely correct on what the issue is. The local LAN address range will take precedence. So you’ll need to change the address range on your LAN to something unique, otherwise it won’t work.

Wow, thank you for confirming! Glad I didn’t waste more time troubleshooting and trying to find a way around it.

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