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TUCoPS :: Networks :: 96.txt

DDN Mailbridge Status

DDN MGT Bulletin 96              DISA DDN Defense Communications System   
16 April 1992                     Published by: DDN Network Info Center
                                      (NIC@NIC.DDN.MIL)  (800) 365-3642

                        DEFENSE  DATA  NETWORK
                         MANAGEMENT  BULLETIN

  The DDN MANAGEMENT BULLETIN is distributed online by the DDN Network
  Information Center under DISA contract as a means of communicating
  official policy, procedures and other information of concern to
  management personnel at DDN facilities.  Back issues may be read
  through the TACNEWS server ("@n" command at the TAC) or may be
  obtained by FTP (or Kermit) from the NIC.DDN.MIL host []
  using login="anonymous" and password="guest".  The pathname
  for bulletins is ddn-news/ddn-mgt-bulletin-nn.txt (where "nn" is the
  bulletin number).
                        DDN Mailbridge Status

    This bulletin addresses a change in the status of the Defense Data
    Network (DDN) Mailbridges (MB).  Request widest dissemination.
1.  As of April 20, 1992, the Mailbridges will no longer
    provide store-and-forward services to the non-MILNET Internet
    (commonly known as NSFNET), and they will no longer provide
    reachability information about NSFNET via External Gateway Protocol
    (EGP).  Mailbridges will continue, though, to provide MILNET
    reachability information.  The following sections address these 
    changes in Mailbridge functionality in detail:
    	-- FIX-West Cisco
    	-- Connectivity to NSFNET
    	-- Default Gateways for Internet Traffic
    	-- Mailbridge Reconfiguration
    	-- EGP Server Assignments
2.  A Cisco has been installed on Node 16 as the replacement for the
    store-and-forward functionality of the BMILAMES Mailbridge on the west
    coast.  This Cisco will become operational after April 13, 1992 as  The status of the FIX-West Cisco is similar to the Ft.
    Detrick Cisco--it will only provide store-and-forward functionality
    (not EGP route server functionality).  
3.  As of April 20, 1992, the Mailbridge at FIX-West (BMILAMES) will
    no longer provide store-and-forward service for packets destined for
    NSFNET.  None of the Mailbridges will have reachability information
    about NSFNET (though they will continue to have MILNET reachability
    information).  Any packet sent to any Mailbridge destined for
    NSFNET will receive an ICMP 'Network Unreachable' message.
    All references to BMILAMES ( as a default gateway for
    Internet traffic should be changed to the FIX-West Cisco (
    Between April 13 and April 20, both the FIX-West Cisco and BMILAMES
    will provide store-and-forward functionality to MILNET hosts.  After
    April 20, BMILAMES will provide EGP route server functionality only.
    The FIX-West Cisco (, together with the Cisco at Ft.
    Detrick (, will connect the MILNET and NSFNET.
    Note that MILNET hosts and gateways that must send traffic to a
    statically configured default gateway should use the FIX-West Cisco at
    ( or the Ft. Detrick Cisco ( for their static
4.  Due to memory limitations, the routing tables in the Mailbridges are
    unable to store routing information for more than 3750 networks .
    The Mailbridges, therefore, will eliminate NSFNET information from their
    routing tables and EGP updates.  Instead, they will be configured to
    distribute a default gateway via either a default network of,
    or a default network of, the NSFNET backbone network.
    A configuration change for the mailbridges will be made to reflect the
    changes at FIX-West. This patch (patch 17), to be deployed on April
    21, 1992, will configure the Mailbridges as specified here:
      MB      	  Mode      Network         Primary         Secondary
    		            Advertised      Default         Default
    BMILAMES 	 "Net NSF"  FIX-West-Cisco     Detrick
    BMILISI		 "Net 0"    FIX-West-Cisco     Detrick
    BMILOAK		 "Net NSF"  FIX-West-Cisco     Detrick
    BMILRAN		 "Net NSF"  FIX-West-Cisco     Detrick
    BMILANDR	 "Net NSF"    Detrick	  FIX-West-Cisco
    BMILDCEC	 "Net NSF"    Detrick	  FIX-West-Cisco
    BMILRICH	 "Net 0"      Detrick	  FIX-West-Cisco
    "Net NSF" implies that the Mailbridge will advertise one default network
    for all NSFNET routes-- 

    "Net 0" implies that the Mailbridge will advertise net as
    the default network for all NSFNET routes.
    For example, gateways receiving information from EGP sessions with
    BMILAMES will be told to default NSFNET traffic via network with a next hop being the FIX-West Cisco.  If the FIX-West
    Cisco is down, it will advertise the Detrick Cisco as the next hop to
    For Cisco routers that are unable to use a default network of,
    it is recommended that they configure an 'ip default-network'.
    To reiterate, ALL Mailbridges will distribute limited (MILNET only)
    updates.  In addition, BMILAMES, BMILOAK, BMILRAN, BMILANDR, and
    BMILDCEC will advertise network, and BMILISI and BMILRICH
    will advertise network
5.  EGP Server Assignment
    As stated in DDN Management Bulletin 83, Section 6, connectivity (in
    the near future) between MILNET and NSFNET will be provided via IP
    routers on the T1-backbone. A new assignment for EGP servers and
    Internet traffic accompanying these changes will be announced prior
    to the deployment of this connectivity plan.
    In the meantime, the use of Mailbridges as EGP servers should
    adhere to the following guidelines:
    a)  Gateways, such as Ciscos, that can utilize a specified default
        network of should use BMILAMES, BMILRAN, BMILANDR.
    b)  Gateways, such as Unix machines running "gated", that can utilize a
        default network of should use BMILISI and BMILRICH.  
    c)  Air Force concentrators should continue to use BMILDCEC and
        BMILOAK.  Note BMILDCEC and BMILOAK will advertise
        instead of as the default network.
    d)  Questions or issues should be directed to the DDN Monitoring Center
        Trouble Desks:
        (1) CONUS: 1-800-451-7413 or (703) 486-1982 or (DSN) 231-1787.
        (2) Europe:  (ETS) 430-5532 or (MIL) 2729-5532 or
              	      (DSN) 314-430-5532 or (CIV) 011-49-680-5532 
        (3) Pacific: (808) 656-1472 or (DSN) 315-456-1472
    e)  The following network addresses apply: 
        Mailbridge     Site Location        Network Address
        BMILAMES       Moffett Field, CA
        BMILANDR       Andrews AFB, MD
        BMILDCEC       Reston, VA 
        BMILISI        Marina Del Rey, CA
        BMILOAK        Oakland, CA
        BMILRAN        Randolph AFB, TX  
        BMILRICH       Richmond, VA
    f)  Specific EGP assignments should follow those given in DDN
        Management Bulletin 83.  However, BMILANDR now replaces BMILMTR,  
        and BMILRICH replaces BMILBBN.  Please note that, as no Mailbridge
        will send EGP Updates larger than 8 Kbytes, 'Net NSF' and 'Net 0'
        now imply the default network advertised rather than the update size
        (see section 4 above).
    g)  Prior to 1 Jun 92, BMILBBN (at MILNET node 72) will be reactivated.
        This is based on PSN 72 being given more robust communications via
        faster ISTs.  Once this has happened, DISA will assess the impact of
        adding the eighth mailbridge.  If this is beneficial, new assignments
        for EGP service will again be issued.  More on this subject will
        follow after reactivation of BMILBBN.

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