Conclusion: First record the externally visible IP and connection conditions
ipconfig displays the IP configured for each adapter on the PC. Home and corporate LANs primarily use private IPs, while web services check the public IP that passes through the router's NAT or upstream network. First, record the active adapter, default gateway, and the source IP and version seen by the web service.
| Check order | What to check | Points of judgment |
|---|---|---|
| 1 | Active adapter in ipconfig | Exclude disconnected and virtual adapters |
| 2 | IPv4 / IPv6 and the default gateway | Values such as 192.168.x.x are for the LAN. |
| 3 | IP and version visible on the Web | Usually compare this for external service authorization |
| 4 | VPN / virtual NIC | Check whether any factors change the path |
Do not confuse Public IP, Private IP, and connection source IP
PCs and smartphones receive an IP address on the LAN, while a web service sees the source IP after NAT, carrier networks, VPNs, proxies, or CDNs. A difference between ipconfig or device network settings and the value shown online does not by itself indicate a problem.
| Notation example | valid range | Main uses |
|---|---|---|
| localhost / 127.0.0.1 / ::1 | The same device | Check your local development server |
| 192.168.x.x etc. | Home/Internal LAN | Connection to router or LAN device |
| Example of 203.0.113.24 etc. | For explanation of Public IP which is unique on the Internet side | Comparison with IP allow list and external logs |
| Example of 2001:db8:1200::24 etc. | Reserved address for IPv6 explanation | Explanation of IPv6 connection/permission range |
Articles and figures use only descriptive addresses reserved by the RFC. Please do not post your IP in screenshots or public issues.
ipconfig displays settings for each network adapter
ipconfig
Windows IP Configuration
Wireless LAN adapter Wi-Fi:
IPv4 Address . . . . . : 192.168.1.10
Default Gateway . . . : 192.168.1.1Adapters for Wi-Fi, Ethernet, VPN, Docker, and virtualization may be listed. Check the adapter and Default Gateway currently used for communication, and do not unconditionally use the first displayed IP.
The router's NAT translates the source IPv4 address
A home router converts the private IPv4 addresses of multiple devices to its external public IPv4 address for communication. Therefore, even if a PC is 192.168.1.10 and the router's LAN side is 192.168.1.1, it can appear to the internet as a different IP such as 203.0.113.24. Check IPv6 separately because it does not necessarily use the same NAT model.
For values registered in a Web service IP allowlist, confirm with the administrator based on the source IP that actually reaches the service.
What you can learn from the IP and connection information checker
| Item | What to display | limit |
|---|---|---|
| Current source IP | IP address seen by DevelopTools with one access to this page | It is not necessarily the IP assigned directly to the PC. |
| IP version | Whether the obtained connection source IP is IPv4 or IPv6 | Even if one is displayed, it cannot be determined that the other cannot be used. |
| IP registration information | Country/Region, City, TimeZone, ASN, Registered Organization | This information does not guarantee your current location or contract. |
| Connection information | HTTP, TLS, Cloudflare connection base, reference RTT | It is not a line speed measurement or route tracking. |
| Items not automatically determined | VPN, Proxy, CGNAT, Hosting, DNS settings | Compare before and after connection and check router/contract information |
This tool displays information that Cloudflare understands about current HTTP connections through /api/ip on the same site. This is not an implementation that transfers IP from the input form to a third party's IP inquiry API. On the other hand, we cannot guarantee that general hosting and Analytics access records do not exist, so avoid sharing publicly.
If the displayed IP is IPv4, it means that "IPv4 was seen when this page was retrieved." This does not prove that IPv6 cannot be used in a Dual Stack environment.
Check additionally if the problem persists
- Use ipconfig /all to check the active adapter, DNS, and DHCP information
- Temporarily isolate VPN / virtual adapters
- Compare the router WAN side and web display
- Check whether the target service was reached over IPv4 or IPv6
With the same URL and same operation, you can change only one condition at a time, such as Wi-Fi and mobile line, VPN OFF and ON, browser and CLI. It will be easier to track route differences by aligning the confirmation date and time, display IP, IP version, error code, and server log time.
IP restrictions are additional access controls. It is not a substitute for authentication or multi-factor authentication, so please also check your WAF/Proxy/authentication settings before expanding the scope of permissions.
Official specifications confirmed in this article
Descriptions of address ranges, OS commands, Proxy headers, CDNs, and containers are based on RFCs and official documentation for each product. Service-specific headers and network specifications are updated, so please double-check the latest official documentation when changing settings.
| Official materials | What was confirmed |
|---|---|
| Microsoft Learn「ipconfig」 | ipconfig displays each network adapter's IPv4/IPv6, subnet, gateway, etc. |
| RFC 1918 | 10/8, 172.16/12, 192.168/16 are private IPv4 address spaces |
| RFC 6598 | 100.64.0.0/10 is a shared address space for carriers and is separate from RFC 1918. |
| RFC 8200 | IPv6 is the successor of IPv4, and the address length is 128 bits. |
| RFC 7239 | While the Forwarded header can convey information that would be lost in a proxy, it still requires trust boundaries and integrity checks. |
| Cloudflare HTTP headers | Via Cloudflare, combine official headers such as CF-Connecting-IP with trusted connection sources |
| Docker bridge network driver | With the default bridge, the host side address is usually visible from the outside due to masquerading. |
| curl official tutorial | Check the connection when IPv6 is obtained through name resolution, fallback to IPv4, and the concept of specifying IPv4/IPv6 |
Example: allowed 192.168.1.10 but received 403
192.168.1.10 shown by Windows ipconfig is a Private IP used only within the LAN. External Web services see the source IP after it passes through a router or similar device.
Open an IP-checking tool on the same connection, confirm a public IP such as 203.0.113.24 (for illustration) and its IPv4 display, then compare it with administrator-side logs.
- Connect to the Wi-Fi where the issue occurs
- Check the active adapter with ipconfig
- Record the source IP and version with an IP check tool
- Compare the allowlist and server logs at the same time
Do not post real IP addresses in public chat. Share only the necessary scope through the designated secure support channel.
Frequently asked questions
- Can I check my global IP with ipconfig?
- Except in special configurations where a Public IP is assigned directly to the PC, the IP visible from the web may not match it on typical home or corporate LANs.
- Is IPv6 also translated through NAT in the same way?
- IPv6 does not assume NAT in the same way as IPv4. Check the actual connection IP separately from router and firewall settings.
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