Is there a way to block junk emails in vBulletin?
How To Avoid Junk Emails in vBulletin?
What Junk emails are you referring of vBulletin? Do you mean the emails that you get from forums you are subscribed to or your own vBulletin forum that is sending emails?
Not my vBulletin forum but my clients.
You can't do much for junk emails being reported by users or even for bounced emails unless you prefer to receive bounced emails and edit those users manually.