Updating existing firewall rule using API

Question

I am able to pro grammatically add individual rules to the Windows Firewall (Server 2008 R2), however I am trying to avoid multiple rules per IP address, and would just like to

Answer 1

The code below works for me:

INetFwPolicy2 firewallPolicy = (INetFwPolicy2) Activator.CreateInstance(Type.GetTypeFromProgID("HNetCfg.FwPolicy2"));

var rule = firewallPolicy.Rules.Item("Block Bad IP Addresses"); // Name of your rule here
rule.Name = "Block Block Block"; // Update the rule here. Nothing else needed to persist the changes

Answer 2

I have found this package it is available via nuget WindowsFirewallHelper

PM> install-package WindowsFirewallHelper

Example

var rule = FirewallManager.Instance.Rules.Where(o => 
    o.Direction == FirewallDirection.Inbound &&
    o.Name.Equals("Allow Remote Desktop")
).FirstOrDefault();

if (rule != null)
{
    //Update an existing Rule
    rule.RemoteAddresses = new IAddress[]
    {
        SingleIP.Parse("192.168.184.1"),
        SingleIP.Parse("192.168.184.2")
    };

    return;
}

//Create a new rule
rule = FirewallManager.Instance.CreateApplicationRule(
     FirewallManager.Instance.GetProfile().Type,
     @"Allow Remote Desktop",
     FirewallAction.Allow,
     null
);

rule.Direction = FirewallDirection.Inbound;
rule.LocalPorts = new ushort[] { 3389 };
rule.Action = FirewallAction.Allow;
rule.Protocol = FirewallProtocol.TCP;
rule.Scope = FirewallScope.All;
rule.Profiles = FirewallProfiles.Public | FirewallProfiles.Private;
rule.RemoteAddresses = new IAddress[] { SingleIP.Parse("192.168.184.1") };

FirewallManager.Instance.Rules.Add(rule);

Answer 3

In addition to amdmax's answer (sorry I can't add a comment) I found that there is no simple method call to check to see if a rule exists so I came up with this to ensure that a rule is created whether it exists or not:

  INetFwPolicy2 firewallPolicy = (INetFwPolicy2)Activator.CreateInstance(
      Type.GetTypeFromProgID("HNetCfg.FwPolicy2"));

  INetFwRule firewallRule = firewallPolicy.Rules.OfType<INetFwRule>().Where(x => x.Name == RULE_NAME).FirstOrDefault();

  if (firewallRule == null)
  {
    firewallRule = (INetFwRule)Activator.CreateInstance(Type.GetTypeFromProgID("HNetCfg.FWRule"));
    firewallRule.Name = RULE_NAME;
    firewallPolicy.Rules.Add(firewallRule);
  }