Hi,
My boss has suddenly started receiving 1000s of messages in his inbox. They are undelivered messages that are bouncing back, though the emails weren't coming from him. I guess either these are fake undelivered messages and are just scam emails. Or they are real emails being sent with spoofed email addresses. Or what other possibilities could it be? and how to find out what it is?
Post is really too vague to comment.
Please make it clear what elements of this issue you control.
Is this a mail server which you control? If so, what Operating System and mail service engine?
Does it normally work?
Is this an internal mail server or one which is connected to the Internet?
What email client does your boss run, and on what Operating System? Whatever email client, please be specific about the software name and version.
Do all your email clients have commercial virus scanners?
To progress this problem we need to be able to display representative email headers without endangering the client computer if they are viral. This is much easier if we can catch the email on a unix email server. If it is a M$ email server it will require M$ expertise.