








       SSmmaaiill -- IInnssttaallllaattiioonn aanndd AAddmmiinniissttrraattiioonn GGuuiiddee

            _R_o_n_a_l_d _S_. _K_a_r_r _<_t_r_o_n_@_u_t_s_._a_m_d_a_h_l_._c_o_m_>
          _L_a_n_d_o_n _C_u_r_t _N_o_l_l _<_c_h_o_n_g_o_@_u_t_s_._a_m_d_a_h_l_._c_o_m_>
                        Amdahl Corp.
                    1250 E. Arques Ave.
                 Sunnyvale, CA  94088-3470



                          _A_B_S_T_R_A_C_T



          SSmmaaiill33..11  is a router and transport agent for
     mail.  It receives  mail  messages  and  recipient
     addresses  from  local  users  and  remote  hosts,
     routes mail destined for  remote  hosts,  performs
     alias  and  forwarding  transformations  on  local
     addresses and performs  delivery.   SSmmaaiill  can  be
     used  in  any  networking environment that expects
     mail to conform to the DDN mail format  standards;
     for  example, the ARPAnet, CS-Net and the interna-
     tional UUCP network.

          The mailer can be used to route mail  between
     any  number  of conforming networks, and can use a
     variety of methods for determining  the  namespace
     on  those  networks  and performing delivery.  The
     three mutually orthogonal operations of  aliasing,
     host  routing  and  transport are all handled in a
     consistent manner  with  consistent  configuration
     file  formats  and C language drivers to implement
     the basic capabilities.

          A number of tools are included in  the  smail
     distribution  which  are useful in building, main-
     taining and displaying databases.  Some  of  these
     tools  operate  on  databases  used  by the mailer
     itself.  Others are  useful  for  users  and  site
     administrators.

          This  paper  describes the ssmmaaiill installation
     procedure, the methodologies to use in  construct-
     ing  configurations, tools for building databases,
     and   administration   concerns   that   must   be
     addressed.



8 June 1994















                 SSmmaaiill -- IInnssttaallllaattiioonn aanndd AAddmmiinniissttrraattiioonn GGuuiiddee

                      _R_o_n_a_l_d _S_. _K_a_r_r _<_t_r_o_n_@_u_t_s_._a_m_d_a_h_l_._c_o_m_>
                    _L_a_n_d_o_n _C_u_r_t _N_o_l_l _<_c_h_o_n_g_o_@_u_t_s_._a_m_d_a_h_l_._c_o_m_>
                                  Amdahl Corp.
                              1250 E. Arques Ave.
                           Sunnyvale, CA  94088-3470


          11..  IInnttrroodduuccttiioonn

               The  ssmmaaiill33..11 program and its associated utilities were
          developed to provide an extensible mailer that  conforms  to
          the  DDN  mail  format  standards in the ARPAnet _R_e_q_u_e_s_t _F_o_r
          _C_o_m_m_e_n_t documents RFC822, RFC920 and RFC976.   It  can  also
          accept  and  transmit  mail  conforming  to the transmission
          envelope format standard described in RFC821.

               A major design goal was to provide extensibility in the
          methods  employed  for resolving local and remote addresses,
          and in the methods used for performing mail delivery.   This
          extensibility is provided through drivers that provide basic
          services on the level of C language  subroutines,  and  run-
          time  configuration files which define parameters that spec-
          ify how these drivers are to used.  The run-time  configura-
          tion  files  are not required, and if they do not exist then
          pre-loaded configurations are used.  This allows many  sites
          to operate with no run-time configuration files.

               Another  goal  was  to  provide a reliable mail service
          that was tolerant of system crashes and capable of  recover-
          ing  from  configuration errors.  To a limited extent, smail
          was also designed to recover from file systems that run  out
          of  space, and from log files that cannot be opened or writ-
          ten to.

               In addition to these and other goals, we felt  that  it
          was  also important that ssmmaaiill be compatible with the exter-
          nal interface of the Berkeley sseennddmmaaiill program.   This  com-
          patibility  applies to the command line options, to as large
          an extent as was feasible, but does not apply to either  the
          internal   operation  or  the  configuration  file  formats.
          Indeed the configuration files for ssmmaaiill  and  for  sseennddmmaaiill
          differ  not only in their format, but also in their philoso-
          phy and in what they describe.  The  sseennddmmaaiill  configuration
          files  describe a syntax-directed model of recipient address
          routing, while the  ssmmaaiill  configuration  files  describe  a
          database  model  of  recipient  address  routing,  and local
          address matching and expansion.








