[Feature Request]: Add Additional CIDR Block for MQTT Private IP Scope

[Xaositek]

Platform

NRF52, ESP32, RP2040, Linux Native, Cross-Platform, other

Description

In the current MQTT isPrivateIpAddress function, there are a set of Private IP ranges acceptable.

I would like to see the following IP range added: 100.64.0.0/10

This range is a private IP CGNAT pool dedicated to TailScale, these are still private IPs and non-internet routable.

TailScale Doc - https://tailscale.com/kb/1304/ip-pool

[caveman99]

This is not tailscale specific but a general CGNAT range. These are not RFC1918 addresses and are used differently. They usually live outside your firewall, while RFC1918 lives inside. This is such a small percentage of users i am really hesitant to add this. If you really need connectivity over these please use a VPN with a RFC1918 address space.

Shared Address Space is similar to [RFC1918] private address space in that it is not globally routable address space and can be used by multiple pieces of equipment. However, Shared Address Space has limitations in its use that the current [RFC1918] private address space does not have. In particular, Shared Address Space can only be used in Service Provider networks or on routing equipment that is able to do address translation across router interfaces when the addresses are identical on two different interfaces.

[caveman99]

Looks like Tailscale really bends the RFC here ...