IP Addresses & CGNAT

The internet operates using two types of IP addresses: IPv4 and IPv6. IPv4, the older standard, has reached its limit, while IPv6, the newer one, is still being adopted, with CGNAT helping to bridge the gap. This page explains the terms and what OFNL providers offer in terms of support.

IP Addresses

When you request a website, its server is found via its IP address. The server sends the response back to you via your public IP address. Essentially, the IP address serves as a unique identifier, similar to a home address.

When people talk about IP addresses, they usually mean IPv4 addresses. They look like this: 172.67.134.87

There are around 3.7 billion public IPv4 addresses - not enough for all the people on the internet, let alone for multiple devices per person. It has been clear since the 1980s that they would eventually run out.

IPv6

There are an unfathomable number of IPv6 addresses - several hundred million to every human on Earth. They look something like this: 2606:4700:3037::6815:1999

Unfortunately, it is not yet universally adopted:

• Updating or replacing older computer systems is often expensive.
• Most users will not see an immediate benefit, so they do not demand its adoption.
• There are workarounds that keep the limited number of IP addresses working well enough.

Until that migration is complete, most internet users still rely on IPv4 for accessing parts of the internet.

Dynamic vs Static IPs

To manage the limited IPv4 addresses, broadband providers will reuse IP addresses when needed. For example, when you restart your router, you will usually end up with a different IP address.

Some people need a static, unchanging IP address, though - and there are providers that offer them. You usually need to pay for extra for this service.

CGNAT

CGNAT is a technology that lets broadband providers share a single IPv4 address across multiple customers. (This is similar to NAT, which lets your home network share a single IP address across all your devices.)

This requires routing web traffic through the broadband provider’s servers, which can increase latency. In addition, services that require connecting directly to your computer via your IP address, like some multiplayer games, peer-to-peer file sharing services or self-hosting a server, can be complicated by NAT and CGNAT. Since the NAT runs on your router, you can change its settings - with CGNAT, those settings are your provider’s. There are workarounds to these problems, but they can make latency even worse and slow the internet speed.

That said, my OFNL provider, Connexin, uses CGNAT, and it has not caused me any problems. I would not treat CGNAT as an disqualifying factor unless you have specific needs - it is unavoidable for lots of people on the internet, given the lack of IPv4 addresses.

What about OFNL?

OFNL does currently not support IPv6 directly, but some providers offer it on top of the OFNL network. The use of CGNAT and the availability of static IP addresses also differ between individual providers.

* This information is largely not publicly available. I have reached out to all OFNL providers and will add missing data if they respond.