Carrier Grade NAT (CGNAT) - jamesmacwhite/hh70-ee GitHub Wiki

Carrier Grade Network Address Translation (CGNAT) is a technology used by a lot of providers in response to IPv4 exhaustion. It is particularly prevalent with mobile networks. The EE mobile network uses CGNAT for IPv4 which by extension also applies to the 4GEE Home Router as it is mobile broadband. The IPv4 address of your 4GEE Home Router will be a CGNAT gateway and not directly routed to you. This can potentially cause issues for certain services mainly:

• Port forwarding
• End to end connectivity on a 1:1 basis
• Gaming (lobbies and parties)
• Ping/IP monitoring (not your own IP)

Most if not all websites should work fine with CGNAT. The issue is more around certain applications and services that perform certain connectivity operations which are not handled properly or do not expect CGNAT to be in place.

To avoid CGNAT you would want to look at a service like Andrews and Arnold L2TP service or similar where you can establish a tunnel to get an IPv4 address/IPv6 prefix that is directly routed to you. There are also some mobile networks like Three UK, which also offer IPv4 without CGNAT on 4G.