Wireless Users Chat → Any ISPs in the US that use Carrier Grade NAT?

Are their any ISPs in the USA that are using Carrier Grade NAT? Any ISP whether it is wireless, cable, dsl or fiber providers?

Um, yeah, lots of ISP's use it. Why?

Because I have ATT wireless, Verizon FiOS, Verizon Wireless, Spring and I have never seen an IP that looks like 100.XXX.XXX.XXX so I assumed it's not used in USA

how are you checking your IP?

ipchicken.com whatismyip.com whoer.net

Those will only show the external IP address. Presuming you are on a CG NAT, there would be potentially thousands of users on the same IP. If you find out the address that is actually assigned to your connected device, it will likely be a different story.

I thought if I am on CG NAT then my external IP would start with 100?

"The Shared Address Space address range is 100.64.0.0/10." according to this link

»tools.ietf.org/html/rfc6598

Those would be the addresses behind the NAT, which public sites cannot address. With a conventional router, you would have to open your modem's configuration page and check its WAN setting to see your actual IP address, then compare it to ipchicken, etc. to determine that you are behind a CG NAT.

Are you sure? I thought with CG NAT the site will see the same public IP from all the users

There are just too many providers using CG NAT for them to all present the same public IP. Apparently, some carriers even route secure traffic differently from nonsecure so you might show different IPs. Take a look at jackal 's post in the following thread and try both spyber links. Also check out ortizdr 's proxy checker in the same thread.

»Gmail shows different IP for ATT cellular then web browser

As AppFarmer said above, the CG NAT range will be an internet set of IP addresses and cannot be routed across the internet. NAT stands for Network Address Translation, aka, many user/devices sharing a public IP. Nobody will ever see a CG NAT address on an IP lookup site like that, as it will only ever show you the shared public IP address.

Think of it like a wireless router. It will get an IP address from your provider, but on the internal network side it will be a bunch of 192.168.x.x addresses all sharing the one IP on the WAN of the router.

CG NAT works similar, except the public IP will be on your providers router, and your router or device will get the "internal" IP addresses on it's WAN port.

There is no real difference between the CG NAT range that is specified and any other private IP range, other than the CG NAT range is supposed to only be used for that so your router treats it like a public IP range and doesn't try to automatically switch to a bridged mode (thanks Apple AirPort for that).

For my ISP, my CG NAT implementation doesn't actually even use the specified CG NAT range, as I had all of the IP addressing setup long before that range was set aside for that purpose. I'm just using one of the existing private IP ranges. My setup has 32 customers sharing each IP address, that way I conserve IP space, but don't stick hundreds or thousands of users behind one IP, which can cause problems also.

No. Even the linked RFC says it's basically the same as RFC1918 address space, it's just intended for use with CGNAT. As such it is a private (internal) address range and will not show up as an external IP.

I remember reading a comment elsewhere on this site that Chet Kanojia’s »Starry.com wireless service uses CGNAT.