Router, Firewall을 거쳐 Remote Site에서 Logon 하는 경우 Open되어야 할 Port

53 (TCP, UDP) - Domain Name System (DNS).
88 (TCP, UDP) - Kerberos authentication.
123 (TCP) - Windows Time Synchronization Protocol (NTP).
135 (TCP) - EndPointMapper.
389 (TCP, UDP) - Lightweight Directory Access Protocol (LDAP).
445 (TCP) - Server message block (SMB) for Netlogon, LDAP conversion and  distributed file system (Dfs) discovery.
3268 (TCP) - LDAP to global catalog servers.