logon to specific OU using Directoryservices
Path: LDAP://my.domain User: DOMAINuser Pass: mypass
DOMAINuser = Autenticated

Path: LDAP://my.domain, ou=myou, dc=my, dc=domain User: user Pass: mypass

Path: LDAP://my.domain/ou=myou User: user Pass: mypass

Path: LDAP://my.domain/ou=myou User: DOMAINuser Pass: mypass

LDAP://servername/ou=MyOU,dc=my,dc=domain

LDAP://ou=MyOU,dc=my,dc=domain  (for server-less binding)

string adPath = "LDAP://ou=myou,dc=my,dc=domain";
string adUser = "myuser";
string adPass = "mypass";

// you might need to play around with the "AuthenticationTypes" to get it to work
DirectoryEntry entry = new DirectoryEntry(adPath, adUser, adPass, AuthenticationTypes.None);

DirectorySearcher searcher = new DirectorySearcher(entry);

searcher.Filter = @"(objectClass=Person)";

string adPath = "LDAP://my.domain/ou=myou,dc=my,dc=domain";

string adPath = "LDAP://dc01.my.domain/ou=myou,dc=my,dc=domain";