Firewall Books For Windows 7

You can drive the Windows Firewall using a COM API, a layer over the Windows Filtering Platform. If you are thinking to develop directly the WFP, it's better to change your idea. WFP is a low level API to build Firewalls and not to be managed directly from traditional applications.

The starting point to use the firewall API in a Visual C++ project is the following statements in the stdafx.h:

#import "netfw.tlb" rename_namespace("fw")
#include <Netfw.h>

The import statement trigger the creation of two files:
netfw.tlh contains things like strong typed smartpointers for the types in the type library (_COM_SMARTPTR_TYPEDEF), enums and interface declarations netfw.tli contains methods that wraps calls and throws exceptions in place of HRESULTs. The rename_namespace directive is the way you can choose the C++ namespace name for all the code created in those two files, in our case "fw". Using the COM API is now very simple. Let's see how to list the firewall rules:

typedef BOOL (*RuleCallback)(fw::INetFwRulePtr& Rule);
void ListRules(RuleCallback Callback)
{
HRESULT hr;
// Connect to the firewall
fw::INetFwPolicy2Ptr Pol2;
hr = Pol2.CreateInstance(__uuidof(fw::NetFwPolicy2));
if(Pol2 == NULL)
return;
// Retrieve collection rules
fw::INetFwRulesPtr Rules = Pol2->Rules;
if(Rules == NULL)
return;
// enumerate the collection and call a callback function
ULONG num;
VARIANT obj;
IEnumVARIANTPtr enumerator = Rules->Get_NewEnum();
while(enumerator->Next(1, &obj, &num) == S_OK)
{
fw::INetFwRulePtr Rule = obj;
if(!Callback(Rule))
return;
}
}

Adding, deleting, and working on service rules, is again very simple.