gistfile1.cs

public SearchRequest GetSearchRequest(string filter, SearchScope scope, string[] attribs, string domainName = null, string adsPath = null)
{
    Domain targetDomain;
    try
    {
        targetDomain = GetDomain(domainName);
    }
    catch
    {
        return null;
    }

    domainName = targetDomain.Name;
    adsPath = adsPath?.Replace("LDAP://", "") ?? $"DC={domainName.Replace(".", ",DC=")}";

    var request = new SearchRequest(adsPath, filter, scope, attribs);
    var soc = new SearchOptionsControl(SearchOption.DomainScope);
    
    request.Controls.Add(soc);
    return request;
}

public LdapConnection GetLdapConnection(string domainName = null)
{
    Domain targetDomain;
    try
    {
        targetDomain = GetDomain(domainName);
    }
    catch
    {
        return null;
    }

    var domainController = _options.DomainController ?? targetDomain.Name;

    var identifier = _options.SecureLdap
        ? new LdapDirectoryIdentifier(domainController, 636, false, false)
        : new LdapDirectoryIdentifier(domainController, false, false);

    var connection = new LdapConnection(identifier);
    
    //Add LdapSessionOptions
    var lso = connection.SessionOptions;
    if (!_options.DisableKerbSigning)
    {
        lso.Signing = true;
        lso.Sealing = true;
    }
    
    if (_options.SecureLdap)
    {
        lso.ProtocolVersion = 3;
        lso.SecureSocketLayer = true;
        if (_options.IgnoreLdapCert)
            connection.SessionOptions.VerifyServerCertificate = (con, cer) => true;
    }

    lso.ReferralChasing = ReferralChasingOptions.None;
    return connection;
}

public IEnumerable<SearchResultEntry> DoSearch(string filter, SearchScope scope, string[] props,
            string domainName = null, string adsPath = null, bool useGc = false)
{
    //Get an LDAP Connection
    using (var conn = useGc ? GetGcConnection(domainName) : GetLdapConnection(domainName))
    {
        if (conn == null)
        {
            yield break;
        }

        //Get a SearchRequest with our options
        var request = GetSearchRequest(filter, scope, props, domainName, adsPath);

        if (request == null)
        {
            yield break;
        }

        //Add a page control to get 500 entries at a time
        var prc = new PageResultRequestControl(500);
        request.Controls.Add(prc);

        if (_options.CurrentCollectionMethod.Equals(CollectionMethod.ACL))
        {
            var sdfc =
                new SecurityDescriptorFlagControl { SecurityMasks = SecurityMasks.Dacl | SecurityMasks.Owner };
            request.Controls.Add(sdfc);
        }

        PageResultResponseControl pageResponse = null;
        //Loop to keep getting results
        while (true)
        {
            SearchResponse response;
            try
            {
                response = (SearchResponse)conn.SendRequest(request);
                if (response != null)
                {
                    pageResponse = (PageResultResponseControl)response.Controls[0];
                }
            }
            catch
            {
                yield break;
            }
            if (response == null || pageResponse == null) continue;
            foreach (SearchResultEntry entry in response.Entries)
            {
                yield return entry;
            }

            //Exit the loop when our page response indicates we're out of data
            if (pageResponse.Cookie.Length == 0 || response.Entries.Count == 0)
            {
                yield break;
            }

            prc.Cookie = pageResponse.Cookie;
        }
    }
}