(No title)

# Dimou on mail configuartions

    Date: Thu, 14 Feb 91 15:37:36 +0100
    From: dimou@cernvax.cern.ch (maria dimou)
    To: timbl@nxoc01.cern.ch

    The following short note was prepared by M. Dimou on request by J. Richards
    and A. Silverman. It was read and commented by D. Wiegandt and it is sent
    to the mintlist for information.

    24/1/91

    --------------- Email policy for unix/ultrix workstations -----------------

     - The owner or the manager of a newly installed workstation, which
       is supposed to be able to send and receive Email should update the
       sendmail configuration file with:

    	    . The complete domain information of the node.
    	      In ultrix systems for example this is represented by the
    	      value of the $D macro i.e. DDcern.ch

    	    . The name of the general purpose relay machine.
    	      Again in the example of ultrix systems this is represented
    	      by the $R macro and it should have the value 'dxmint',
    	      with the alternative of 'cernvax', as a backup relay,
    	      i.e. DRdxmint
    		   #DRcernvax

    	    . Arrange in ruleset zero (S0) for all foreign Email
    	      traffic to be routed via the 'tcplocal' mailer to
    	      the major relay machine (defined in $R in the case of
    	      ultrix and others) and for Email to local users to be
    	      delivered with the 'local' mailer.

    	      The reason for adopting this 'restricted' routing
    	      is to profit from the sophistication built in the sendmail
    	      configuration of the central gateway machines (dxmint and
    	      cernvax), which modifies bogus addresses, giving them a
    	      canonical RFC 822 format (i.e. user@host.domain).

    In case of a group of workstations, installed and operated as a 'cluster':

    	    . To avoid the risk of some of them being
    	      unavailable for incoming SMTP for extended time periods
    	      (for high incoming traffic a few hours are already a problem)
    	      it is advised to fake the hostname on the "From"
    	      address of outgoing messages, replacing the name of the
    	      individual workstation by the name of a well supported
    	      'server' node.
    	      This is how Apollo's at CERN are organized, i.e. they are
    	      all addressed as 'user@cernapo.cern.ch' due to appropriate
    	      facilities in their sendmail.

    	    . For other types of workstations, where such a possibility
    	      doesnot exist, it is sufficient for the 'server' node
    	      to have the usernames of all 'client' workstations' users
    	      defined as aliases.

    	    . The other advantage that such a centralised management
    	      provides, is the availability of disk space for storing
    	      and forwarding the messages to the 'client' workstations.

    --------------- Email policy for VAX/VMS workstations -----------------

    Unfortunately VMS mail is rather 'primitive', giving little
    possibility of protection against system management problems.
    As a minimum, owners of VAX/VMS workstations are advised to:

    	    . Publicise their Email address on a 'bigger' machine
    	      (which has a system manager watching on its availability and
    	      the users' disk space).

    	    . Set an autoforward on that node pointing to the VAXstation
    	      This autoforward should be cancelled when the station
    	      is shut down.

    M. Dimou
    CS/EN