ExtendedRetry statement

Use the ExtendedRetry statement to extend the retry processing that Communications Server SMTP (CSSMTP) uses when it attempts to resend mail messages that are not immediately deliverable. For basic information about extended retry, see the information about common terms in z/OS Communications Server: IP Configuration Guide.

The RetryLimit statement defines the retry interval during which CSSMTP will try sending the mail messages again while the JES spool file is still available. When the long retry interval expires (the interval is the product of multiplying the COUNT and INTERVAL values), the mail messages are copied to a z/OS® UNIX directory for extended retry processing and the JES spool file is released. When the extended retry interval expires, the mail messages become undeliverable.

After both the long retry interval and the extended retry interval retries have expired, the following actions occur when information about the mail sender's address is available:

  1. CSSMTP uses the setting on the ReturnToMailFrom parameter in the UNDELIVERABLE statement to determine its next action.
  2. CSSMTP attempts to send the undeliverable mail notifications to the originator of the mail message through the configured target servers. If CSSMTP cannot send the notification on the first try, the mail message becomes a dead letter (see UNDELIVERABLE statement) and no retries will be made.
Guideline: If the ExtendedRetry statement is not defined in the configuration file, extended retry processing is inactive.
Tip: You can set the Interval parameter on the ExtendedRetry statement to 0 to bypass extended retry processing.

Syntax

Read syntax diagramSkip visual syntax diagramExtendedRetryPut Braces and Parameters on Separate Lines
Put Braces and Parameters on Separate Lines
Read syntax diagramSkip visual syntax diagram{ExtendedRetry Parameters}
ExtendedRetry Parameters
Read syntax diagramSkip visual syntax diagramAge 5Age  daysInterval 30Interval  minutesMailDirectory /var/CSSMTP/ extwrtname/mail/MailDirectory  mailDirectory

Parameters

Age days
Indicates the number of days that CSSMTP attempts to resend mail messages after the extended term retry interval expires. The default value is 5 days. The value 0 means that an unlimited number of retry attempts will be made. The maximum value is 2147483647.
Interval minutes
Indicates the length of time, in minutes, that CSSMTP waits between subsequent attempts to resend mail messages. The default value is 30 minutes. The maximum value is 1440 minutes (one day).

If the Interval value is 0, no extended retry will be performed and a mail message becomes undeliverable if CSSMTP cannot deliver it to the target servers on the first try.

MailDirectory mailDirectory
The fully qualified directory name in the z/OS UNIX file system where CSSMTP stores the mail message when the Interval parameter is set to a nonzero value. Valid values are 1 - 512 characters in length and must begin with a slash (/) to define the fully qualified directory. The default mail directory is /var/cssmtp/extWrtName/mail/, where extWrtName is the name specified in the ExtWrtName statement.
Results:
  • A slash is added to the end of the mail directory name if it is not present.
  • If the mail directory does not exist it is created.
Guidelines:
  • The user ID that CSSMTP starts under must have read/write access to this directory. If you are running multiple CSSMTP servers with extended retry enabled, each server should have its own directory and should not have access to the directories of other servers.
  • Ensure that there is adequate space in the filesystem for extending retry processing. For example, if each mail message is an average of 8000 bytes in size and you expect to have 1000 mail messages to be tried again, then about 16 million bytes of file space is needed [2 (files per mail message) × 8K (z/FS file allocation size) × 1000]. Factor in the 75% threshold for message EZD1862I, then the file system should be about 22 million bytes in size (plus a margin of error).
  • The size of the MailDirectory is the sum of all of the size of all the mail messages saved for extended retry at any one time.
Restrictions:
  • If extended retry processing is activated, you must stop and restart CSSMTP in order to change the name of the mail directory.
  • If CSSMTP is active, you cannot change the name of the mail directory and you cannot delete or change the files.
  • The content of the files created by CSSMTP and stored in the mail directory cannot be modified.

Tip: You can configure your mail directory to be on a different z/OS UNIX file system than where you have configured your deadletter directory. By doing this, you can manage the resource better. For more information, see UNDELIVERABLE statement.