Adding an application firewall rule to both private and public networks via win7 FirewallAPI

Question

A little background: Basicaly I\'d like to add a program firewall access rule to both private and public networks.

I used to use this- \"netsh firewall add allowedpr

Answer 1

This page doesn't say this has been answered and is old, so just in case, for future use, I'll answer this.

First, import reference FirewallAPI.dll, located at "C:\Windows\System32\FirewallAPI.dll", then add the using directive

using NetFwTypeLib;

The inboundRule.Profiles property seems to be classified as a set of flags with the following values (the property's type is an int, so i made an enum):

public enum FirewallProfiles
{
    Domain = 1,
    Private = 2,
    Public = 4
}

So, with that code, we can change the Profiles to the following:

// Create a new rule
INetFwRule2 inboundRule = (INetFwRule2)Activator.CreateInstance(Type.GetTypeFromProgID("HNetCfg.FwRule"));
// Enable the rule
inboundRule.Enabled = true;
// Allow through firewall
inboundRule.Action = NET_FW_ACTION_.NET_FW_ACTION_ALLOW;
// Using protocol TCP
inboundRule.Protocol = 6; // TCP
// Set port number
inboundRule.LocalPorts = "1234";
// Name of rule
inboundRule.Name = "Name Of Firewall Rule";
// Set profiles
inboundRule.Profiles = (int)(FirewallProfiles.Private | FirewallProfiles.Public);

// Add the rule
INetFwPolicy2 firewallPolicy = (INetFwPolicy2)Activator.CreateInstance(Type.GetTypeFromProgID("HNetCfg.FwPolicy2"));
firewallPolicy.Rules.Add(inboundRule);

Or you could change inboundRule.Profiles to an int value.

Two notes:

1: If you don't run this code under administrative privilege's,

firewallPolicty.Rules.Add(inboundRule);

will throw an exception.

2: inboundRule.Profiles must be between values 1 and 7. Otherwise, it will throw an exception