First there is an attribute mode which will tell to the module how to deliver the mails. 0 means direct connect, you need to setup the DNS server in that case. 1 means use a gateway in that case you have to setup up smtp user/password as well as the gateway
SMTP connectioin timeouts. This was a problem and the site jboss.org was not able to deliver mails because of the fact that the default values on javamail are infinite. So if one delivery was blocking on a read, the thread was blocked there. I added values so you can parametrize that. The default value is 4 seconds.