If the Java mail is trying to send mail to non-existent mail ID say firstname.lastname@example.org (or one which has mailbox full) what will happen? Will it try delivering that message for a specified time period? I am getting many error messages from my SMTP server saying - "SMTP; 550 Requested action not taken: mailbox unavailable"
Is it something that needs to be tweaked at SMTP level or can I do something to set Java mail API properties such that retry time is less. This problem is slowing down my system with too many open connections. I am wondering what I can do - though we do email ID validation, there is no way at the moment to see if mailbox is really available or not. What can I do here?
If the Java mail is trying to send mail to non-existent mail ID say email@example.com (or one which has mailbox full) what will happen?
It will be sent to a server for pqr.com and (possibly) be returned.
SMTP doesn't include any standard mechanism to report delivery failure. This is deliberate; given the environment SMTP is supposed to work in (the internet) there is the very real posibility that a failure message will not be returned.
So you have two problems:
That no failure message will be returned
That, if a message is returned, you don't have a guarenteed way of correlating which message failed.
You can get round the second by setting flags in your mail and reading them from incoming mails. There is no solution to the first problem.