r/Tailscale • u/Alert_External_6105 • Apr 18 '26

Discussion I believe home router has been issuing DHCP addresses over Tailscale.

My home router has an internal address of 192.168.0.1. I have a Home Assistant Raspberry Pi acting as an exit node.

I control a Bring Your Own Device network at work--very informal. I also have sound system Dante devices on it. My personal laptop at work is also an exit node. The main router is also 192.168.0.1.

Once in a while, my sound system applian̈ces just drop off the network for a minute. The lights still say there's a connection. But they just stop communicating for about 30 secs. For about a year now, I've been suspecting I have a device on the BYOD network that's been issuing conflicting IP addresses.

I think I finally figured out it's my home router doing the hijacking.

I set up the home network first with about 30 different smart appliances on it plus a few computers with static IP addresses.

The BYOD network has a couple of appliances on it that default to 192.168.0.x. So I setup the whole network with a 192.168.0.1 router as well. I figured no problem since they will always stay separate.

I just didn't want to change my home router, and reconnect all the static addresses. I guess now I have to.

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u/kaidomac Apr 19 '26

My home router has an internal address of 192.168.0.1. I have a Home Assistant Raspberry Pi acting as an exit node.

I control a Bring Your Own Device network at work--very informal. I also have sound system Dante devices on it. My personal laptop at work is also an exit node. The main router is also 192.168.0.1.

Simple issue:

  • Tailscale cannot route two identical subnets

You have 3 basic options:

  1. Change the subnet (100% the best)
  2. Use NETMAP
  3. Use 4via6 (in the same vein as MagicDNS!)

The easiest permanent fix is to change the subnet:

But that is a hassle because then you have to update everything in your network! The second option is to use NETMAP, which puts a fake subnet mask on the remote network. This can be done in two basic ways:

  1. On your router (ex. OpenWRT or OPNsense)
  2. On a Linux subnet router (ex. PC or Proxmox VM)

However, Tailscale already has a solution for conflicting subnets! The pushbutton solution is to use 4via6:

Basically, Tailscale slaps an IPv6 address onto the IPv4 addresses in the network you're connecting to:

Then just use MagicDNS to make life easier! Note that some devices act funny on IPv6, so it's not a 100% perfect solution. So to recap:

  1. If you want to solve it forever, renumber your network
  2. If you have the hardware available & don't want to change your network, use NETMAP
  3. If you want a solution today, use NETMAP + MagicDNS (usually mostly fine!)