README

   1 The pmg-log-tracker extracts information out of the syslog to match all entries
   2 related to a single mail. It does so by using the PID of 'smtpd' entries in the
   3 log as key for the SEntry structs. The QID, an ID consisting of at least 2 all
   4 upper case hex digits, is used for both QEntry structs and FEntry structs.
   5
   6 As a rule of thumb, SEntrys are used wherever the services 'postscreen' and
   7 'smtpd' are involved. QEntrys on the other hand are only used when a queue is
   8 involved (e.g. after-queue filtering passing the postscreen checks,
   9 before-queue filtering when the mail is 'accepted'). FEntrys are used whenever
  10 the filter (pmg-smtp-filter) is involved.
  11
  12 The typical flow of a mail (after-queue):
  13
  14 1. postscreen (NOQUEUE -> mail finished)
  15 2. smtpd (pid matching)
  16 3. cleanup -> qmgr (mail in queue, QID matching)
  17 4. pmg-smtp-filter (rule system, accept/block, long (Q)ID matching)
  18 5. lmtp/smtp/local/error (QID matching, filter ID matching in lmtp)
  19 6. qmgr ('removed')
  20 7. smtpd ('disconnected from')
  21
  22 Both 6 and 7 are required before the mail can be printed completely.
  23 6 and 7 can be logged in arbitrary order.
  24
  25 The typical flow of a mail (before-queue):
  26
  27 1. postscreen (NOQUEUE -> mail finished)
  28 2. smtpd 1 (pid matching)
  29 3. pmg-smtp-filter (rule system, accept/block, long (Q)ID matching)
  30   - on accept match the QID
  31 4. smtpd 2 (pid matching)
  32 5. (optional, only on 'accept') cleanup -> qmgr (mail in queue, QID matching)
  33 6. (optional, only on 'accept') smtp (QID matching)
  34 7. (optional, only on 'accept') qmgr ('removed')
  35 8. smtpd 2 ('disconnect from')
  36 9. smtpd 1 (proxy-accept/proxy-reject, filter (Q)ID matching)
  37 10. smtpd 1 ('disconnect from')
  38
  39 7, 8 and 10 are required before the mail can be printed completely.
  40 7, 8 and 10 can be logged in arbitrary order.