IP Helper API (iphlpapi)

Overview

The IP Helper API provides a set of functions and data structures that enable applications to retrieve and modify network configuration settings on Windows operating systems. It includes capabilities for enumerating adapters, interfaces, IP addresses, routing tables, and more.

Functions

Function	Description
`GetAdaptersInfo`	Retrieves adapter information for the local computer.
`GetIfTable`	Retrieves a table of interface entries.
`GetBestInterface`	Determines the interface best suited for a destination IP address.
`GetIpAddrTable`	Retrieves the IP address table.
`GetNetworkParams`	Retrieves network parameters such as DNS servers and domain name.
`InitializeWinsock`	Initializes the Windows Sockets library.
`ResolveIP`	Resolves a host name to an IP address.

Structures

IP_ADAPTER_INFO
MIB_IFTABLE
MIB_IPADDRTABLE
FIXED_INFO
IP_ADAPTER_UNICAST_ADDRESS

Constants

#define MAX_ADAPTER_NAME_LENGTH 256
#define MAX_ADAPTER_DESCRIPTION_LENGTH 128
#define ERROR_BUFFER_OVERFLOW 111
#define ERROR_SUCCESS 0

Code Samples

Enumerate Network Adapters (C++)

#include <windows.h>
#include <iphlpapi.h>
#pragma comment(lib, "iphlpapi.lib")

int main() {
    DWORD size = 0;
    GetAdaptersInfo(nullptr, &size);
    IP_ADAPTER_INFO *info = (IP_ADAPTER_INFO*)malloc(size);
    if (GetAdaptersInfo(info, &size) == NO_ERROR) {
        for (IP_ADAPTER_INFO *p = info; p; p = p->Next) {
            wprintf(L"Adapter: %S\n", p->AdapterName);
            wprintf(L"Description: %S\n", p->Description);
            wprintf(L"IP: %s\n", p->IpAddressList.IpAddress.String);
        }
    }
    free(info);
    return 0;
}