string myServerName = "111.22.333.444:389";

string myUserName = "MyLogin,ou=Systems,ou=LOCATION,o=Internal,dc=MYCOMPANY,dc=COM";

string myPassword = "MyPassword";

string myDomain = "ou=Systems,ou=LOCATION,o=Internal,dc=MYCOMPANY,dc=COM";

LdapConnection myConnection = new LdapConnection(myServerName);

NetworkCredetial myCredential = new NetworkCredential(myUserName, myPassword, myDomain);

myConnection.Bind(myCredential);