public class IISAdministration

{

    private readonly ServerManager serverManager;

    public IISAdministration()

    {

        serverManager = new ServerManager();

    }

    public IEnumerable<WorkerProcess> GetWorkerProcesses()

    {

        return serverManager.WorkerProcesses;

    }

    public IEnumerable<string> GetSiteNames()

    {

        foreach (var item in GetWorkerProcesses())

        {

            yield return item.AppPoolName;

        }

    }

    public ConfigurationElementCollection GetIpSecurityCollection(string site)

    {

        return GetConfigurationElementCollection("system.webServer/security/ipSecurity", site);

    }

    public ConfigurationElementCollection GetConfigurationElementCollection(string sectionName, string site = "")

    {

        var config = serverManager.GetApplicationHostConfiguration();

        ConfigurationSection section;

        if (string.IsNullOrWhiteSpace(site))

        {

            section = config.GetSection(sectionName);

        }

        else

        {

            section = config.GetSection(sectionName, site);

        }

        return section.GetCollection();

    }

    public void CreateElement(ConfigurationElementCollection section, ConfigurationElement element)

    {

        section.Add(element);

        serverManager.CommitChanges();

    }

    public void RemoveElement(ConfigurationElementCollection section, ConfigurationElement element)

    {

        section.Remove(element);

        serverManager.CommitChanges();

    }

    public bool HasBlocked(string siteName, string ip)

    {

        var ipSecurityCollection = this.GetIpSecurityCollection(siteName);

        for (int i = 0; i < ipSecurityCollection.Count; i++)

        {

            var element = ipSecurityCollection[i];

            if ((string)element["ipAddress"] == ip)

            {

                return true;

            }

        }

        return false;

    }

    public void FreeIP(string siteName, string ip)

    {

        if (!HasBlocked(siteName, ip))

        {

            return;

        }

        var ipSecurityCollection = this.GetIpSecurityCollection(siteName);

        for (int i = 0; i < ipSecurityCollection.Count; i++)

        {

            var element = ipSecurityCollection[i];

            if ((string)element["ipAddress"] == ip)

            {

                this.RemoveElement(ipSecurityCollection, element);

                break;

            }

        }

    }

    public void BlockIP(string siteName, string ip)

    {

        if (HasBlocked(siteName, ip))

        {

            return;

        }

        var ipSecurityCollection = this.GetIpSecurityCollection(siteName);

        var element = ipSecurityCollection.CreateElement("add");

        element["ipAddress"] = ip;

        element["allowed"] = false;

        ipSecurityCollection.Add(element);

        serverManager.CommitChanges();

    }

}

var iisAdministration = new IISAdministration();

iisAdministration.BlockIP("", "192.0.0.1");