MTA Logging – Sending to a Nonexistent Domain

This example illustrates an attempt to send to a nonexistent domain (here very.bogus.com); that is, sending to a domain name that is not noticed as nonexistent by the MTA's rewrite rules and that the MTA matches to an outgoing TCP/IP channel. This example assumes the MTA option settings of LOG_FILENAME=1 and LOG_MESSAGE_ID=1.

When the TCP/IP channel runs and checks for the domain name in the DNS, the DNS returns an error that no such name exists. Note the “rejection” entry (R), as seen in (5), with the DNS returning an error that this is not a legal domain name, as seen in (6).

Because the address is rejected after the message has been submitted, the MTA generates a bounce message to the original sender. The MTA enqueues the new rejection message to the original sender (1), and sends a copy to the postmaster (4) before deleting the original outbound message (the R entry shown in (5)).

Notification messages, such as bounce messages, have an empty envelope From: address—as seen, for instance, in (2) and (8)—in which the envelope From: field is shown as an empty space. The initial enqueue of a bounce message generated by the MTA shows the message ID for the new notification message followed by the message ID for the original message (3). (Such information is not always available to the MTA, but when it is available to be logged, it allows correlation of the log entries corresponding to the outbound failed message with the log entries corresponding to the resulting notification message.) Such notification messages are enqueued to the process channel, which in turn enqueues them to an appropriate destination channel (7).

Example 21–4 MTA Logging – Sending to a Nonexistent Domain

19-JAN-1998 20:49:04 l            tcp_local    E 1
  adam@sesta.com rfc822;user@very.bogus.com user@very.bogus.com
  imta/queue/tcp_local/ZZ01ISKP0S0LVQ94DU0K.00
 <01ISKP0RYMAS94DU0K@SESTA.COM>
 
19-JAN-1998 20:49:33 tcp_local    process      E 1                (1)
 rfc822;adam@sesta.com adam@sesta.com                             (2)
 imta/queue/process/ZZ01ISKP0S0LVQ94DTZB.00
 <01ISKP22MW8894DTAS@SESTA.COM>,<01ISKP0RYMAS94DU0K@SESTA.COM>    (3)

19-JAN-1998 20:49:33 tcp_local    process      E 1                (4)
 rfc822;postmaster@sesta.com postmaster@sesta.com
 imta/queue/process/ZZ01ISKP0S0LVQ94DTZB.00
 <01ISKP22MW8894DTAS@SESTA.COM>,<01ISKP0RYMAS94DU0K@SESTA.COM>
 
19-JAN-1998 20:50:07 tcp_local                  R 1               (5)
 adam@sesta.com rfc822;user@very.bogus.com user@very.bogus.com
 imta/queue/tcp_local/ZZ01ISKP0S0LVQ94DU0K.00
 <01ISKP0RYMAS94DU0K@SESTA.COM>
 Illegal host/domain name found                                   (6)

19-JAN-1998 20:50:08 process      l            E 3                (7)
 rfc822;adam@sesta.com adam                                       (8)
 imta/queue/l/ZZ01ISKP23BUQS94DTYL.00
 <01ISKP22MW8894DTAS@SESTA.COM>
 
19-JAN-1998 20:50:08 process      l            E 3
  rfc822;postmaster@sesta.com postmaster
  imta/queue/l/ZZ01ISKP23BUQS94DTYL.00
 <01ISKP22MW8894DTAS@SESTA.COM>
 
19-JAN-1998 20:50:12 l                         D 3
  rfc822;adam@sesta.com adam
  imta/queue/l/ZZ01ISKP23BUQS94DTYL.00
  <01ISKP22MW8894DTAS@SESTA.COM>
 
19-JAN-1998 20:50:12 l                         D 3
  rfc822;postmaster@sesta.com postmaster
  imta/queue/l/ZZ01ISKP23BUQS94DTYL.00
  <01ISKP22MW8894DTAS@SIROE.COM>