Validate existing emails and prune accounts automatically

[erkme73]

I've found a couple of threads for mods and hacks that do something like this, but nothing specific - and certainly nothing for 3.6.4.

From the start, I've always required email validation during activation. Unfortunately, there were a number of people who tried to 'fake' the system, causing me to end up with a bunch of 'user awaiting email confirmation' accounts. While I could simply delete all accounts that have been in this usergroup for more than x days, I think that's too brutal.

I also have problems with legitimate, validated accounts (registered users) who have changed their emails. They don't know it, but when the board sends out notifications of new posts, or mass emails, they get bounced.

The last mass-email I did, I was swamped with over 300 user unknown bounced emails.

I'd like for the forum to be able to register the bounced email and either send the user a PM with a warning (i.e. that they have 10 days to update their email or their account will be suspended/deleted), or outright delete it.

The one hack I did find only checks the MX listing to make sure the domain is valid - but doesn't validate specific email addresses. That makes it usless, since many of the invalid emails I have were, at one point, valid.

Any help would be appreciated!