You can configure the SMTP server, port number, and security identity for the EmailOutput node as a broker external resource.
Use an alias that is specified in the SMTP Server and Port property on the EmailOutput node. There is no need to restart after using the mqsichangeproperties command to change SMTP configurable service values. The security identity references a user ID and password pair that is defined on the broker by using the mqsisetdbparms command. As documented for the mqsisetdbparms command, you must stop and start each integration server that uses a particular DSN, before the information that was modified by the mqsisetdbparms command is read and used by that integration server.