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Which IP do ChatGPT and Claude actually see? Why a clean US IP still gets blocked

A common puzzle: an IP checker shows a clean US address, yet ChatGPT or Claude says the region isn’t supported, or keeps asking for verification. Usually the IP isn’t the problem — the AI site simply isn’t seeing that IP.

At a glance: which IP each site seesProxy apps route by rules. The IP checker may go over line A in the US, while chatgpt.com and claude.ai go over line B, another country or a datacenter IP. A checker only sees the IP you used to reach it. At a glance: which IP each site sees Opening an IP checker Line A Browser Proxy rules US exit A checker only sees the IP you used to reach it Opening ChatGPT or Claude Line B Browser Proxy rules Another countryor datacenter IP This is the IP the AI site actually sees To check it, open chatgpt.com/cdn-cgi/trace
A US result on a checker only tells you line A is in the US. Check which line chatgpt.com and claude.ai use separately.

Why they differ

Most proxy apps route by rules that decide which sites use the proxy and which line they use. The checker’s domain, chatgpt.com and claude.ai can end up on different lines, or not on the proxy at all. So the checker sees line A in the US, while chatgpt.com goes over line B — another country, or a datacenter IP. A checker only sees the IP you used to reach it.

Ask the AI sites directly, in the browser

Both chatgpt.com and claude.ai sit behind Cloudflare, which offers a diagnostic page showing the IP and region used to reach that site. Open:

  • https://chatgpt.com/cdn-cgi/trace
  • https://claude.ai/cdn-cgi/trace

ip= is the IP that site sees, and loc= is the country code (e.g. US). These are the values that matter.

The IP Judge home page does this for you: it reads the IP seen by claude.ai and chatgpt.com and flags any difference from the IP you used to open the page.

Terminal tools need their own check

Command-line tools such as Claude Code and Codex use the terminal’s network settings, which may differ from the browser’s. In the same terminal, run:

curl -s https://chatgpt.com/cdn-cgi/trace | grep -E '^(ip|loc)='

Repeat with claude.ai, or run curl ipjudge.org/en for the full verdict on the terminal’s exit.

Check browser and terminal separatelyIn the browser, open /cdn-cgi/trace on chatgpt.com and claude.ai. For terminal tools, run curl in the same terminal. ip= is the IP that site sees; loc= is the country code. Check browser and terminal separately In the browser Open https://chatgpt.com/cdn-cgi/trace https://claude.ai/cdn-cgi/trace Claude Code, Codex Same terminal curl -s https://chatgpt.com/cdn-cgi/trace | grep -E '^(ip|loc)=' Then repeat with claude.ai ip= the IP that site sees loc= the country code (e.g. US) The IP Judge home page checks both and flags any difference.
The terminal’s network settings may differ from the browser’s, so read ip= and loc= in both.

Two more things to check

  • WebRTC: if the proxy doesn’t handle UDP, any web page can read another of your IPs through WebRTC. The IP Judge home page shows the WebRTC IP and flags it when it differs from your exits.
  • Time zone: a browser time zone that doesn’t match the exit region is another signal platforms can see. Proxy apps can’t change the system time zone; set it yourself.

Troubleshooting order

  1. Confirm the IP and region chatgpt.com and claude.ai see are the line you expect.
  2. Check the region is on OpenAI’s and Anthropic’s supported lists. Mainland China, Hong Kong and Macau are not.
  3. Check the IP’s type and risk: datacenter IPs and anything flagged as proxy or VPN get challenged more often.
  4. Keep browser, terminal and phone on the same exit, and avoid hopping between countries.

Which kind of IP do you have?

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