Checklist for working within the SMTP environment

SMTP needs to interface with JES utilities to create, read, write and purge data from the JES spool. JES exit programs might interfere with SMTP functioning properly.
JES initialization parameters must be set up correctly so mail can be sent to SMTP and so that local mail can be placed on the JES spool for local users.
Because SMTP needs authority to create, read, write, and purge data on the JES spool, any security programs that protect JES spool access must have the user ID or group ID that is associated with the SMTP started task name in their definitions of authorized users. If your security product is RACF®, you can control the association of a user ID or group ID to a started task name by the STARTED class. For more information about RACF controls for the JES spool, see z/OS Security Server RACF Security Administrator's Guide.
DASD management is important to have SMTP run properly, it is recommended that SMTP have its own dedicated volumes. The MAILFILEVOLUME statement can be used to specify a particular volume where newly allocated SMTP data sets are. See z/OS Communications Server: IP Configuration Reference for more information on this parameter.
SMTP is a heavy user of data set I/O functions. It creates data sets for every piece of mail it processes. There are two data sets associated with each piece of mail:
1. SMTPhlq.*.ADDRBLOK (control file)
2. SMTPhlq.*.NOTE (message content)
The SMTP high level qualifier (SMTPhlq) is configured in the SMTP configuration data set using the MAILFILEDSPREFIX statement. When SMTP is executing, SMTP must have exclusive access to the data sets it has created to work properly.
To avoid contention, applications that manage DASD should be run only when SMTP is not active, or exclude the SMTP data sets or the volumes where the SMTP data sets are from their processing. If contention occurs, EZA5335E will be displayed before the SMTP server terminates. Also, the SMTP high level qualifier can be used to exclude the SMTP data sets if necessary.
SMTP requires that the ASCII LineFeed character (x'0A') be translated to an EBCDIC LineFeed (x'25'). The translation table used by SMTP must have this translation. For information regarding customizing translation tables and for the search order used by SMTP to locate the translation table, see z/OS Communications Server: IP Configuration Reference.