You can configure the SMTP server, port number, and security identity for the EmailOutput node as an integration node external resource.
Use an alias that is specified in the SMTP Server and Port property on the EmailOutput node. The security identity refers to a user ID and password pair that is defined on the integration server 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.