Tailcat – Like netcat, but over Tailscale’s data plane

Re:Tailcat – Like netcat, but over Tailscale’s data plane by linsomniac on Wednesday August 26, 2026 @05:33PM (#49456246)

I was just wondering yesterday if it'd be possible to have a tailscale client, or multiple tailscale clients in their own network namespaces, that could connect to multiple networks.

The slightly tricky part would be managing a local NAT that blends the two networks, and also does MagicDNS to answer on those NATed IPs. If routes conflicted, I guess you'd have to pick one?

Seems very doable though.

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Re:Tailcat – Like netcat, but over Tailscale’s data plane by maisem on Wednesday August 26, 2026 @06:19PM (#49456707)

yeah that's kinda what it does. It sets up two tsnet servers connected to two different tailnets and exposes them through a shared TUN device. It does the magic of allocating safe IPs to each host so that they don't overlap and does some leasing so that IPs aren't accidentally reassigned. It also does the MagicDNS thing so that DNS returns the "effective IP".

I wanted it to work on macOS so couldn't rely on network namespaces.

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Re:Tailcat – Like netcat, but over Tailscale’s data plane by linsomniac on Wednesday August 26, 2026 @07:55PM (#49457546)

That deserves it's own top-level discussion, for sure! https://news.ycombinator.com/item?id=49457539

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Re:Tailcat – Like netcat, but over Tailscale’s data plane by linsomniac on Wednesday August 26, 2026 @05:33PM (#49456249)

@bradfitz: Steal this idea ^^^ ;-)

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