How do I find out a public IP address on the Internet using the Win32 API?

Question

How do I find out a public IP address on the Internet using the Win32 API?

I am interested in the public ip address, not the IP address of the local network. Interested in IPv4 and IPv6.

Now I find out my ip address like this: I go to some site that determines the ip address, and the site tells me my ip address. I need to do this using the Win32 API.

I am interested in the Win32 API, and not any programming languages (C++, C#, etc.).

Answer 1

Yes, you need to use an external website.

For example with Wininet on my PC :

					HINTERNET hInternet = InternetOpen(NULL, INTERNET_OPEN_TYPE_PRECONFIG_WITH_NO_AUTOPROXY, NULL, NULL, 0);
					if (hInternet != NULL)
					{
						HINTERNET hFile = InternetOpenUrl(hInternet, _T("https://api.ipify.org"), NULL, 0, INTERNET_FLAG_RELOAD, 0);
						if (hFile != NULL)
						{
							CHAR sBuffer[MAX_PATH];
							TCHAR wsBuffer[MAX_PATH];
							DWORD nRead;
							BOOL bRet = InternetReadFile(hFile, sBuffer, sizeof(sBuffer), &nRead);
							if (bRet)
							{
								sBuffer[nRead] = '\0';
								MultiByteToWideChar(CP_ACP, 0, sBuffer, -1, wsBuffer, MAX_PATH);
								TCHAR wsMessage[MAX_PATH] = _T("");
								wsprintf(wsMessage, _T("External IP : %s"), wsBuffer);
								MessageBox(NULL, wsMessage, _T("Information"), MB_OK | MB_ICONINFORMATION);
							}
							InternetCloseHandle(hFile);							
						}
						InternetCloseHandle(hInternet);
					}

Answer 2

David Lowndes, what is a web service? A regular website or something else? I'm just not an expert in this.

RLWA32, is it impossible to find out the public api address using the Win32 API?

Answer 3

The conclusion is that using the Win32 API, it is impossible to find out the IP address of a computer if the computer is connected to the Internet through a router. In this case, you need to use a website that identifies the ip address. Right?

Answer 4

Gary Nebbett, are you suggesting using Win32 API functions or something else?