Comment by AnssiH
3 hours ago
> These mobile phone providers do not let the gazillion consumer smartphones act as servers for obvious reasons.
FWIW, I was interested so I tested this on my phone here in Finland (Elisa, the largest carrier here): IPv6 inbound TCP connections work just fine, unlike IPv4 which is behind CGNAT.
On mobile broadband (no calls) plans they also offer optional free public IPv4 address, but not on the regular phone plans.
(I did the test by installing Termux from Play Store, then in it running "pkg install netcat-openbsd" and "nc -6 -l 9956" and then connecting to that port from internet using telnet, while phone was not connected to WiFi.)
When you say no ipv4 on regular phone plan, you mean no routable ipv4 on the internet, or no ipv4 at all?
Regular phone plans on my carrier have a private IPv4 address behind CGNAT.