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

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().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);
  }