100.64.0.0/10 is reserved for CGNAT providers to assign to CPE. If you don't connect to a CGNAT then there's nothing stopping you from using it, however. Tailsc

100.64.0.0/10 is reserved for CGNAT providers to assign to CPE. If you don't connect to a CGNAT then there's nothing stopping you from using it, however. Tailscale hands out addresses in 100.100 for that reason (deconflict with customer private networks) https://en.m.wikipedia.org/wiki/IPv4_shared_address_space https://en.m.wikipedia.org/wiki/IPv4_shared_address_space