有时候在代码中我们需要检测防火墙的状态变化，就可以使用windows提供的API函数

#include <windows.h>
#include <crtdbg.h>
#include <netfw.h>
#include <objbase.h>
#include <oleauto.h>
#include <stdio.h>

#pragma comment( lib, "ole32.lib" )
#pragma comment( lib, "oleaut32.lib" )


HRESULT WindowsFirewallInitialize(OUT INetFwProfile** fwProfile)
{
	HRESULT hr = S_OK;
	INetFwMgr* fwMgr = NULL;
	INetFwPolicy* fwPolicy = NULL;

	_ASSERT(fwProfile != NULL);

	*fwProfile = NULL;

	do {
		// 创建防火墙设置管理器的实例
		hr = CoCreateInstance(__uuidof(NetFwMgr), NULL, CLSCTX_INPROC_SERVER, __uuidof(INetFwMgr), (void**)&fwMgr);
		if (FAILED(hr))
		{
			printf("CoCreateInstance failed: 0x%08lx\n", hr);
			break;
		}

		// 检索本地防火墙策略
		hr = fwMgr->get_LocalPolicy(&fwPolicy);
		if (FAILED(hr))
		{
			printf("get_LocalPolicy failed: 0x%08lx\n", hr);
			break;
		}

		// 检索当前有效的防火墙配置文件
		hr = fwPolicy->get_CurrentProfile(fwProfile);
		if (FAILED(hr))
		{
			printf("get_CurrentProfile failed: 0x%08lx\n", hr);
			break;
		}
	} while (0);

	// 释放本地防火墙策略
	if (fwPolicy != NULL)
	{
		fwPolicy->Release();
	}

	// 释放防火墙设置管理器
	if (fwMgr != NULL)
	{
		fwMgr->Release();
	}

	return hr;
}

HRESULT WindowsFirewallIsOn(IN INetFwProfile* fwProfile, OUT BOOL* fwOn)
{
	HRESULT hr = S_OK;
	VARIANT_BOOL fwEnabled;

	_ASSERT(fwProfile != NULL);
	_ASSERT(fwOn != NULL);

	*fwOn = FALSE;

	// 获取防火墙的当前状态
	hr = fwProfile->get_FirewallEnabled(&fwEnabled);
	if (FAILED(hr))
	{
		printf("get_FirewallEnabled failed: 0x%08lx\n", hr);
		return hr;
	}

	if (fwEnabled != VARIANT_FALSE)
	{
		*fwOn = TRUE;
	}

	return hr;
}

void WindowsFirewallCleanup(IN INetFwProfile* fwProfile)
{
	// 释放防火墙配置文件
	if (fwProfile != NULL)
	{
		fwProfile->Release();
	}
}

int main()
{
	HRESULT hr = S_OK;
	INetFwProfile* fwProfile = NULL;
	HRESULT comInit = E_FAIL;


	// 为当前线程初始化COM库并设置并发模式(这个函数没太理解是干什么用的) 
	comInit = CoInitializeEx(0, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE);
	if (comInit != RPC_E_CHANGED_MODE)
	{
		hr = comInit;
		if (FAILED(hr))
		{
			printf("CoInitializeEx failed: 0x%08lx\n", hr);
			return -1;
		}
	}

	//检索当前有效的防火墙配置文件
	hr = WindowsFirewallInitialize(&fwProfile);
	if (hr != S_OK)
	{
		printf("WindowsFirewallInitialize failed\n");
		return -1;
	}

	//判断防火墙是否开启
	BOOL fwOn;
	hr = WindowsFirewallIsOn(fwProfile, &fwOn);
	if (hr != S_OK)
	{
		printf("WindowsFirewallIsOn failed\n");
		return -1;
	}

	if (fwOn)
	{
		printf("Firewall on\n");
	}
	else 
	{
		printf("Firewall off\n");
	}

	WindowsFirewallCleanup(fwProfile);

	system("pause");
	return 0;
}

我们可以使用cmd命令开启关闭防火墙进行验证

#关闭防火墙
netsh advfirewall set allprofiles state off
#开启防火墙
netsh advfirewall set allprofiles state on

源代码地址：Exercising the Firewall using C++ (Windows) | Microsoft Docs

参考：windows防火墙添加规则 - dozeoo - 博客园 (cnblogs.com)