The server is not operational

Question

This is the code I'm using to connecting to LDAP

 using (DirEntry = new DirectoryEntry(string.Format("LDAP://{0}/{1}", this.Host, ServerName)))
        {
            DirEntry.RefreshCache();
            if (!string.IsNullOrEmpty(UserName))
            {
                DirEntry.Username = UserName;
                DirEntry.Password = PassWord;
            }
            if (DirEntry.Properties.Contains("objectGUID"))
            {
                byte[] guiddatet = (byte[])DirEntry.Properties["objectGUID"].Value;
                return new Guid(guiddatet);
            }

I get "The server is not operational" error message when I run the code.

Can someone please tell me where I'm doing it wrong. And is there anyway to replace the above code with direct LDAP query.

Answer 1

You should try breaking this into separate parts, so it's easier to manage the logic, and easier to locate where your errors are occurring. I usually go with the following approach in this situation :

• Create an LdapConnection object so you can set the options you need
• Setup a NetworkCredential instance with an administrative username and password
• Bind to the directory with the user so you can issue a direct LDAP query
• Return a SearchResultEntry so you can process the properties

You have a few options to help you accomplish this, but I'd try something like this :

//Delcare your Network Credential with the administrative Username, Password, and your active directory domain
var credentials = new NetworkCredential(userName, password, domain);

//Create a directory identifier and connection, 
var ldapidentifier = new LdapDirectoryIdentifier(serverName, port, false, false);
var ldapconn = new LdapConnection(ldapidentifier, credentials);

Next, make sure you're setting the right AuthType for your particular instance. Since you're connecting over port 389, just use AuthType.Basic.

ldapconn.AuthType = AuthType.Basic;

As you had asked, there is a very easy way to setup a direct LDAP query using this approach. I'm assuming you're searching by sAMAccountName, but you can modify this as needed :

string ldapFilter = "(&(objectCategory=person)(objectClass=user)(&(sAMAccountName={{UserYouAreTryingToFind}})))";

Now we just have to setup the search request, and send it accordingly :

//Send the search request with our delimited attribute list
var getUserRequest = new SearchRequest(domain, ldapFilter, SearchScope.Subtree, AttributeList)
                                     {SizeLimit = 1};

//Suppress any refferal creation from happening during the search
var SearchControl = new SearchOptionsControl(SearchOption.DomainScope);
getUserRequest.Controls.Add(SearchControl);
var userResponse = (SearchResponse)ldapconn.SendRequest(getUserRequest);

//This is where I load up the entry I've located, 
SearchResultEntry ResultEntry = userResponse.Entries[0];

That should return the user you've queried for, along with any properties you've put into AttributeList. In this context, AttributeList is just a string array (string[]) of property names - in your case you'll want to add one called "objectGUID".

As for reading the properties on the SearchResultEntry, you can do exactly what you had originally :

 if(ResultEntry.Attributes.Contains("objectGUID"))
 {
     // do some stuff here
 }

That should help get you going in the right direction.

Also, if you don't already have a copy of wireshark, I highly suggest you download it - it will be invaluable in diagnosing connection issues with active directory.