Flow diagram of using fetchmail and SpamAssassin with sendmail
to proxy and filter Lotus Notes/Domino and remote POP3 mail.

Joey Kelly, joey@joeykellynet, fall 2002


                   +---------+          +-------+
+-------+  types   | sending |  calls   |sending|  
| Alice |--------->|   MUA   |--------->|  MTA  |::::>::::
+-------+          |         |          |       |       ::
                   +---------+          +-------+       ::   on the
                                                        ::   sending
                             SMTP                       ::   machine
 ::::::::::::::::::::::::::::<::::::::::::::::::::::::::::
 ::
.::.......................................................................
 ::
 ::   +---------+          +-----+             +-------+
 ::   |receiving|  calls   |     |  delivers   | Bob's |
 ::::>|   MTA   |--------->| LDA |============>|server |::::>::::
      |         |          |     |    to       |mailbox|       ::  on the
      +---------+          +-----+             +-------+       ::   mail
                                                               ::  server
                          POP or IMAP                          ::
 ::::::::::::::::::::::::::::<:::::::::::::::::::::::::::::::::::
 ::
.::........................................................................
 ::
 ::                  +-----------+ 
 ::                  |           |
 :::::::>::::::::::::| fetchmail |::::::::               on the
                     |           |      ::              receiving
                     +-----------+      ::               machine,
                                        ::             with fetchmail
      ::::::::::::::::<:::::::::::::::::::
      :: 
      ::   +---------+          +-----+                +-------+
      ::   |receiving|  calls   |     |  delivers to   | Bob's |
      ::::>|   MTA   |--------->| LDA |===============>|mailbox|:::>::::
           |         |          |     |                |       |      ::
           +---------+          +-----+                +-------+      ::
                                 |   |                                ::
                                 |   |                                ::
                                 v   v                                ::
                            +--------------+                          ::
                            | pipe through |                          ::
                            | SpamAssassin |                          ::
                            +--------------+                          ::
                                                                      ::
          ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
          ::
          ::      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          ::     /                                 \
          ::    { +--------+         +------------+ }
          ::    } |   MTA  |         |     MUA    | {
          :::::>{ |  Lotus |-------->| Bob' Lotus | }
                } | Domino |         |    Notes   | {
                { +--------+         +------------+ }
                 \                                 /
                  \   Lotus Domino/Notes cloud    /
                   \                             /
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~