# CGNAT.wtf

> A crowd-sourced, source-cited database of whether you can self-host on each US home internet provider: CGNAT by default,
> public/static IP options, IPv6, typical upload, inbound ports 25/80/443, and what each ISP's terms say about running servers. ISP facts only.

Every field links to its source and carries a source type (official, official-forum, community, secondary). The CGNAT answer
has a confidence level (high = the ISP's own documentation, medium = partly official, low = customer reports only).
"Unknown" means not verified yet, not "no". 41 ISPs tracked; CGNAT answers sourced for 28. Data last verified 2026-10-17.

## Data
- [Open data page](https://cgnat.wtf/data/): what each JSON file contains, its shape, caching and CORS.
- [Full dataset (JSON)](https://cgnat.wtf/data/isps.json): every ISP, every field, with value, note, sources, quotes and confidence. CORS-enabled.
- [Self-host verdicts (JSON)](https://cgnat.wtf/data/selfhost.json): yes/maybe/no/unknown per ISP and use, with the reasons and sources.
- [Host report rows (JSON)](https://cgnat.wtf/data/hostreport.json): compact per-ISP CGNAT default, opt-out, static IP and price, IPv6 and server terms, used by the checker's report.
- [ASN map (JSON)](https://cgnat.wtf/data/asn.json): ISP slug to ASNs (checked against public network registry records), used by the checker.

## Key pages
- [All ISPs](https://cgnat.wtf/): sortable table
- [Can I self-host? check](https://cgnat.wtf/self-host-check/): pick an ISP and a use (web, mail, game, media, remote, cameras, files, voip) for a yes/maybe/no from the dataset, linkable as ?isp=<slug>&use=<key>; answers in https://cgnat.wtf/data/selfhost.json
- [ISP finder](https://cgnat.wtf/finder/): filter by state, CGNAT, IPv6, static IP, upload and inbound ports 25/80/443 (query string, e.g. ?state=TX&cgnat=no)
- [ISPs that use CGNAT](https://cgnat.wtf/isps-that-use-cgnat/)
- [ISPs without CGNAT](https://cgnat.wtf/isps-without-cgnat/)
- [Static IP prices by US home ISP](https://cgnat.wtf/static-ip-prices/): residential vs business-only fees, cited
- [ISPs by state](https://cgnat.wtf/states/)
- [ISP changes log](https://cgnat.wtf/changes/): dated, cited changes to ISP CGNAT, static IP, IPv6 and server rules; Atom feed at https://cgnat.wtf/changes/feed.xml
- [What is CGNAT?](https://cgnat.wtf/what-is-cgnat/)
- [How to tell if you're behind CGNAT](https://cgnat.wtf/guides/how-to-tell-if-youre-behind-cgnat/)
- [Public IP on your ISP (hub)](https://cgnat.wtf/guides/public-ip/): official paths for T-Mobile Home, Verizon 5G Home, AT&T Internet Air, Starlink, T-Mobile Fiber, Metronet, WOW!, Cox, Xfinity, Spectrum, Frontier, Optimum, Nextlink, Hughesnet
- [CGNAT IP range 100.64.0.0/10](https://cgnat.wtf/guides/cgnat-ip-range-100-64/)
- [Why ISPs use CGNAT](https://cgnat.wtf/guides/why-isps-use-cgnat/): IPv4 exhaustion, shared ports, logging, IPv6
- [Why do I keep getting CAPTCHAs or blocked?](https://cgnat.wtf/guides/cgnat-captchas-and-ip-blocks/): shared IPv4 under CGNAT, rate limits, blocklists, what to ask your ISP (RFC 6269, RFC 7021)
- [Self-hosting behind CGNAT (hub)](https://cgnat.wtf/guides/self-hosting-behind-cgnat/): media server, game server, home automation, cameras, remote desktop, file server, mail server and voice/video calls; what breaks and the ISP-side fixes
- [Strict or moderate NAT type and CGNAT](https://cgnat.wtf/guides/nat-type-strict-cgnat/): NAT mapping/filtering (RFC 4787), why CGNAT makes it worse (RFC 6888, RFC 7021)
- [No IPv4 on your router: DS-Lite, 464XLAT and MAP-T](https://cgnat.wtf/guides/no-ipv4-ds-lite-464xlat-map-t/): IPv6-only lines that share IPv4 (RFC 6333, 6877, 7596, 7597, 7599), how to spot them, self-hosting impact
- [Home mail server behind CGNAT](https://cgnat.wtf/guides/mail-server-behind-cgnat/): port 25 blocks by ISP (from the per-port data), submission port 587 (RFC 5068), reverse DNS
- [Voice and video calls behind CGNAT](https://cgnat.wtf/guides/voip-video-calls-behind-cgnat/): what works and what breaks (RFC 8445, RFC 8656, RFC 7021)
- [All guides](https://cgnat.wtf/guides/)
- [CGNAT checker](https://cgnat.wtf/checker/): compares your router's WAN IP with your public IP; port test, IPv6 and NAT type hints; step 5 sums it up as "Can I host from home?" with a share link to https://cgnat.wtf/report/ (coarse results in the URL fragment only, no IP address)
- [Submit a correction](https://cgnat.wtf/submit/)
- Per-ISP pages: https://cgnat.wtf/isp/<slug>/ (slugs are in the dataset), e.g. https://cgnat.wtf/isp/starlink/

## Notes
- Policies change; check the linked source before relying on a fact.
- Contact: hello [at] cgnat [dot] wtf