Create firewall rule to open port per application programmatically in c#

Marek picture Marek · Dec 13, 2011 · Viewed 15.8k times · Source

I need to open specific port for my application.

I have tried using INetFwAuthorizedApplication rule per application for all ports.

fwMgr.LocalPolicy.CurrentProfile.AuthorizedApplications.Add(app)

Alternatively open one port for all appllications using INetFwOpenPort.

firewallManager.LocalPolicy.CurrentProfile.GloballyOpenPorts.Add(port)

Is there any way to programmatically open only single port per application programmatically? I can do it manually through firewall settings.

Answer

Colin Pickard picture Colin Pickard · Dec 14, 2011

There's a question about blocking connections with an answer with instructions for creating firewall rules in C#. You should be able to adapt this for any kind of firewall rule I imagine.

https://stackoverflow.com/a/1243026/12744

The following code creates a firewall rule that blocks any outgoing connections on all of your network adapters:

using NetFwTypeLib; // Located in FirewallAPI.dll
...
INetFwRule firewallRule = (INetFwRule)Activator.CreateInstance(
    Type.GetTypeFromProgID("HNetCfg.FWRule"));
firewallRule.Action = NET_FW_ACTION_.NET_FW_ACTION_BLOCK;
firewallRule.Description = "Used to block all internet access.";
firewallRule.Direction = NET_FW_RULE_DIRECTION_.NET_FW_RULE_DIR_OUT;
firewallRule.Enabled = true;
firewallRule.InterfaceTypes = "All";
firewallRule.Name = "Block Internet";

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