Which US ISPs use CGNAT?
These home internet providers put some or all customers behind carrier-grade NAT, based on the sources on each ISP page. Behind CGNAT, port forwarding won't work unless you get a public IPv4.
| ISP | CGNAT | Opt-out | IPv6 | Server rules |
|---|---|---|---|---|
| Spectrum (Charter) | Some plans/areas partly official | Unknown | Yes | No explicit ban |
| AT&T Internet Air | Yes partly official | No | Unknown | Unknown |
| T-Mobile Home Internet | Yes partly official | No | Yes | Unknown |
| Starlink | Yes official | Paid | Yes | Unknown |
| Cox | Some plans/areas reports | Free opt-out | Yes | Unclear |
| Frontier Fiber (Verizon) | Some plans/areas official | Unknown | Partial | Restricted |
| Mediacom | Some plans/areas official | Unknown | Unknown | Restricted |
| WOW! | Yes partly official | Free opt-out | Unknown | Unknown |
| Metronet | Yes reports | Paid | No | Restricted |
| EPB Fiber | Some plans/areas reports | Free opt-out | Unknown | No explicit ban |
| Hughesnet | Yes reports | Unknown | Unknown | Unknown |
| Greenlight Networks | Yes reports | Paid | Yes (unsupported) | Restricted |
| GCI | Some plans/areas reports | Unknown | Unknown | Limited |
| T-Mobile Fiber (Lumos) | Yes reports | Paid | No | Unknown |
| Nextlink Internet | Yes official | Paid | Unknown | Unknown |
15 of 41 ISPs we track. 14 still have an unverified CGNAT answer, so they aren't listed on either page. The confidence tag shows whether the answer comes from the ISP itself ("official"), partly from the ISP ("partly official") or only from customer reports ("reports"). What is CGNAT? · How to tell if you're behind it