Restriction of NetBIOS on the MCEN SIPRNET

REF A IS THE PORTS, PROTOCOL AND SERVICES (PPS)
MANAGEMENT PROGRAM.
REF B IS THE DOD PORTS, PROTOCOLS AND SERVICES ASSURANCE 
CATEGORY ASSIGNMENT LIST THAT PROVIDES TECHNICAL GUIDANCE ON
CONFIGURATION SETTINGS FOR KNOWN COMBINATIONS OF PPS FOR DOD
INFORMATION SYSTEMS THAT ARE VISIBLE TO DOD MANAGED NETWORK
COMPONENTS. 
REF C IS JTF-GNO COMMUNICATIONS TASKING ORDER 06-12.
GENTEXT/REMARKS/1. THE PURPOSE OF THIS MESSAGE IS TO CLARIFY
MARINE CORPS POLICY ON THE USE OF FILE SHARING PROTOCOLS AND 
SERVICES TO INCLUDE, BUT NOT LIMITED TO: NETBIOS, SERVER MESSAGE 
BLOCK (SMB), COMMON INTERNET FILE SYSTEM (CIFS), AND FILE TRANSFER 
PROTOCOL (FTP) ACROSS THE MARINE CORPS ENTERPRISE NETWORK (MCEN) 
SECRET INTERNET PROTOCOL ROUTER NETWORK (SIPRNET). 
2. BACKGROUND. 
A. THESE PROTOCOLS AND SERVICES ALLOW APPLICATIONS ON INDIVIDUAL 
COMPUTERS TO COMMUNICATE. TYPICALLY FILE SHARING SERVICES AND 
PROTOCOLS ARE USED TO ENABLE FILE AND PRINT SHARING CAPABILITIES 
ON A LOCAL AREA NETWORK. WHEN THESE PROTOCOLS AND SERVICES ARE 
USED TO COMMUNICATE OUTSIDE OF THE LOCAL ENCLAVE THEY ALLOW OTHERS 
CONNECTED TO THE INTERNET, ACCESS TO MACHINES WITH THESE PROTOCOLS 
AND SERVICES ENABLED. 
B. RECENT SCANS OF THE SIPRNET HAS SHOWN CONTINUOUS USE OF THESE
FILE SHARING PROTOCOLS AND SERVICES ACROSS THE MCEN SIPRNET. THIS
ROUTINE USE OF THESE FILE SHARING PROTOCOLS AND SERVICES (EXAMPLE
NETBIOS) EXPOSES THE NETWORK TO UNACCEPTABLE VULNERABLITY LEVELS. 
3. POLICY
A. THE USE OF FILE SHARING PROTOCOLS AND SERVICES EXTERNAL TO THE
MCEN SIPRNET IS STRICTLY PROHIBITED. FILE SHARING PROTOCOLS AND
SERVICES ARE AUTHORIZED ONLY WHEN CONFINED TO THE LOCAL ENCLAVE
(BASE, POST,STATION)AND DOES NOT CROSS SIPRNET BOUNDARIES OR
ENCLAVES UNLESS APPROVED BY THE MCEN DAA. 
4. QUESTIONS MAY BE DIRECTED TO THE POCS CITED.