Is LDAP a TCP or a UDP protocol?
Normally LDAP is a TCP protocol. But Microsoft uses LDAP also over UDP. See here:http://msdn.microsoft.com/en-us/library/cc717362(v=prot.10).aspx
So it is both.
Lightweight Directory Access Protocol (LDAP)The Lightweight Directory Access Protocol: The protocol accessing data from directory services like OpenLDAP, Microsoft Active Directory, Netscape Directory Server or Novell eDirectory.
Protocol dependenciesTCP/UDP: Typically, LDAP uses TCP or UDP (aka CLDAP) as its transport protocol. The well known TCP and UDP port for LDAP traffic is 389.
SSL/TLS: LDAP can also be tunneled through SSL/TLS encrypted connections. The well known TCP port for SSL is 636 while TLS is negotiated within a plain TCP connection on port 389.