1
Read the Verdict
Read the verdict: Proxy detected, Tor detected, VPN or proxy likely, or No proxy detected. Each of the three checks below it shows what it found.
Proxy Checker |
Three checks on your connection: proxy headers, Tor exit list and datacenter / VPN networks.
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What Is a Proxy Checker?
Proxy Checker tells you whether your connection goes through a proxy, Tor or a VPN, using three checks on the IP address websites see: proxy addresses in the X-Forwarded-For header, the Tor Project's exit node list, and whether the IP belongs to a datacenter or VPN-provider network. A VPN or proxy that uses a home IP address and adds no header cannot be detected this way.
How to Use the Proxy Checker
Open the Proxy Checker page. It shows the IP address websites see and checks it automatically.
2
Check the Header Addresses
Look at your X-Forwarded-For header. An address marked "Added by a proxy" is usually the address the proxy received your request from; open it in IP WHOIS Lookup to see its network.
3
Understand a Clean Result
No proxy detected means a direct connection, or a VPN or elite proxy that uses a home IP address and adds no header.
What the Results Mean — Proxy Anonymity Levels
What each check can see depends on the type of proxy. The header check depends on what the proxy writes in X-Forwarded-For; the network check depends on where the proxy's IP comes from.
| Proxy Type | X-Forwarded-For Header | Real IP Visible to Server | Detected by This Tool |
|---|---|---|---|
| Transparent | Present — includes real client IP | Yes | ✅ Yes |
| Anonymous | Present — proxy IP or a fake address, real IP hidden | No | Only if it adds an address other than its own, or runs on a datacenter network |
| Elite (High-Anonymity) | Absent — suppressed by the proxy | No | Only if it runs on a datacenter network |
| Commercial VPN | Absent | No | Usually — most exit from datacenter networks |
| Residential proxy or VPN | Absent | No | ❌ No — looks like a home connection |
A "No proxy detected" result therefore means your connection is direct, or you use a proxy or VPN with a home IP address that adds no header. These two cases look the same from the server.
How Proxy Detection Works — X-Forwarded-For Header Analysis
When an HTTP request passes through a proxy server, the proxy typically appends its IP address
and the original client IP to the X-Forwarded-For header before forwarding the
request. The result is a comma-separated chain of IP addresses recording every intermediate hop.
RFC 7239 (Forwarded HTTP Extension) standardizes this concept through the formal
Forwarded header, though X-Forwarded-For remains the dominant
de facto implementation across proxy software.
This site runs behind Cloudflare, which adds the address that connected to it (the IP websites see) to the end of the header. This tool reads the full X-Forwarded-For chain and labels each address: your IP, Cloudflare's published IPv4 and IPv6 ranges (this site's own network), or an address added before your request reached Cloudflare. That last kind was written by a proxy in front of you, and is usually the address the proxy received your request from — your device or the previous hop — not the proxy itself. Only IP addresses are read; anything else in the header is shown as "Not an IP address".
The two other checks look at the IP itself. The Tor check compares it with the Tor Project's public list of exit nodes, downloaded again every hour. The network check finds the IP's autonomous system (ASN) in the GeoLite2 database and looks it up in a list of about 940 hosting, datacenter and VPN-provider networks. The same two checks power the Privacy line on the What Is My IP page.
Common Proxy Detection Scenarios
Corporate network audit. A sysadmin at a mid-size company notices unexpected source IPs in application logs from internal users. Running Proxy Checker from a workstation inside the network shows "Proxy detected": the corporate firewall added the workstation's internal address (such as 10.0.4.17) to the X-Forwarded-For header — confirming that outbound traffic goes through a proxy before reaching the internet. This is expected behavior in many enterprise environments and is used for traffic filtering and logging.
Verifying proxy type before a privacy-sensitive task. A user has configured an anonymous proxy for a specific browsing session. Before proceeding, they visit Proxy Checker. The header check is clean, but the verdict is "VPN or proxy likely": the proxy's IP belongs to a hosting network. Websites using the same kind of network data will treat the visit as proxied. The user now knows the real IP is hidden, but the proxy itself is visible.
ISP transparent proxy discovery. A user in a region where ISPs commonly intercept traffic expects to see "No Proxy Detected." Instead, the header check lists an address added by a proxy, often a private or carrier-grade NAT address (such as 100.64.12.9) from the ISP's network. This confirms the ISP is routing connections through a transparent caching or content-filtering proxy — a practice common in some regions that most users are unaware of. RFC 7239 permits intermediaries to document themselves in the Forwarded header precisely for transparency in such deployments.
Frequently Asked Questions
How does the Proxy Checker detect a proxy server?
It runs three checks on your connection. First, it reads the X-Forwarded-For header: an address that is neither your IP nor Cloudflare's published ranges was added by a proxy. Second, it checks your IP against the Tor Project's list of exit nodes, refreshed every hour. Third, it checks whether your IP's network (its ASN) is on a list of about 940 datacenter, hosting and VPN-provider networks.
How accurate is the proxy detection?
Each check is reliable for one case. The header check catches proxies that add your address to X-Forwarded-For, which transparent proxies do. The Tor check catches Tor exits on the official list. The network check catches most commercial VPNs and proxies, because they run on datacenter networks, but it is a strong hint, not proof: a business may host servers on the same networks. A VPN or proxy that uses a home (residential) IP and adds no header passes all three checks.
Why does the tool show no proxy detected when I'm using one?
Elite proxies and VPNs add no X-Forwarded-For header, so the header check sees a direct connection. They are then found only by the network check, when their IP belongs to a datacenter or VPN-provider network. Residential proxies and VPNs that use home IP addresses look like normal home connections, so no check here can see them.
What is the difference between a transparent proxy and a high-anonymity proxy?
A transparent proxy forwards the original client IP address inside the X-Forwarded-For header — both the proxy IP and the real client IP are visible to the destination server. A high-anonymity (elite) proxy includes no X-Forwarded-For header at all, so the destination server sees only the proxy's IP with no indication that a proxy is involved.
Does WhatIsMyIPNow store or log the connections it checks?
No. The checks run in real time on the server: the header is read from your request, and your IP is compared with the Tor exit list and the network database kept on our server, so your IP is not sent to any other service. No IP addresses, forwarding headers, or connection data are stored or logged.
What should I do if a proxy server is detected in my connection?
If the proxy is intentional, the result shows that websites can detect it: a header proxy may even pass on your real or local IP. For stronger privacy, use a proxy that adds no header, or a VPN. If the result was unexpected, contact your network administrator — your ISP or company network may route traffic through a filtering or caching proxy without telling you.