EXPN command—Verify whether a mailbox exists on the local host

Purpose

Use the EXPN command to verify whether a given mailbox exists on the local host.

Format

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>>-EXPN--mailbox-----------------------------------------------><

Parameters

mailbox
Specifies a user-defined identifier for a mailbox. This name can specify a single mailbox or a mailing list.

Examples

Verify whether mike is a mailbox on host abc.com:
SMTP client:  EXPN mike
SMTP server:    250 mike@abc.com
 
Verify whether users-hackers is a mailing list on host abc.com:
SMTP client:  EXPN users-hackers
SMTP server:    250-carol@abc.com
                250-greg@abc.com
                250-marsha@abc.com
                250 peter@abc.com
 
The hyphen (-) as the fourth character of a response indicates that the response is continued on the next line.

Usage

  • The EXPN command operates exactly the same as the VRFY command.
  • The EXPN command can verify the existence of one or more mailboxes on the system. The mailboxes are defined by configuration statements in the SMTP.SMTP.CONFIG data set.
  • The MVS™ SMTP server verifies only TSO user IDs if RACF® is installed on the local system. TSO user IDs that are verified as valid are accepted with a reply code of 250. If RACF is not installed, any character string up to eight characters is accepted with a reply code of 250.