I would like to remind about the port requirement ... CIFS uses UDP ports 137 and 138, and TCP ports 139 and 445. The filer sends and receives data on these ports while providing CIFS service. If it is a member of an Active Directory domain, the filer also must make outbound connections destined for DNS (Port 53 UDP and TCP) and Kerberos (Port 88 and 464). Incoming Port 137 - NBNS - (UDP) we listen for name queries and respond if we recognize ours. Outgoing Port 137 - NBNS - (UDP) we are a client of the name service. Outgoing Port 138 - NBDS - (UDP) we are a client of the datagram service. Incoming Port 139 - NBSS - (TCP) CIFS server. Incoming Port 445 - CIFS over TCP (TCP) CIFS server. Outgoing Port 139 - NBSS - (TCP) Cifs client (for contacting DC, virus scanners, etc.). Outgoing Port 445 - (TCP) Same as outgoing 139, above. Outgoing Port 88 - (TCP, maybe UDP) Kerberos Outgoing Port 464 - (TCP, maybe UDP) Kerberos Key administration