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 update the existing rule RemoteAddresses. Below is the code I am using to add rules, I am doing my best to research how to update the existing rules Remote Addresses, but with no luck.

Any help is appreciated!

string ip = "x.x.x.x";

INetFwRule2 firewallRule = (INetFwRule2)Activator.CreateInstance(Type.GetTypeFromProgID("HNetCfg.FWRule"));

firewallRule.Name = "Block Bad IP Addresses";
firewallRule.Description = "Block Nasty Incoming Connections from IP Address.";
firewallRule.Action = NET_FW_ACTION_.NET_FW_ACTION_BLOCK;
firewallRule.Direction = NET_FW_RULE_DIRECTION_.NET_FW_RULE_DIR_IN;
firewallRule.Enabled = true;
firewallRule.InterfaceTypes = "All";
firewallRule.RemoteAddresses = ip;

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

Please avoid prefixing your questions with C# or the like, that is what the tags are for. — M.Babcock
– M.Babcock, Commented Mar 15, 2012 at 1:41

amdmax · Accepted Answer · 2012-03-15 05:58:47Z

13

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

answered Mar 15, 2012 at 5:58

amdmax

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5 Comments

Mohammad Arshad Alam Over a year ago

is there any way to unblock the blocked IP, I mean to say update the rule

Jeroen K Over a year ago

You can change rule.RemoteAddresses (comma separated)

HABO Over a year ago

Tip for those testing this code: The changes are persisted as described, but may not appear in the Windows Firewall with Advanced Security application until after the display is refreshed.

FindOutIslamNow Over a year ago

That uses NetFwTypeLib COM library

tmm1 Over a year ago

What if there are multiple rules with the same name? Windows seems to automatically create two for my app (one for UDP and one for TCP).

Slade · Accepted Answer · 2014-06-04 08:49:18Z

6

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);
  }

answered Jun 4, 2014 at 8:49

Slade

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Comments

live2 · Accepted Answer · 2019-10-17 21:18:12Z

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);

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