Some from outside was able to send an email to all my email recipients. How? He sent it to email@example.com. I notice that whenever you create a distribution list in Exchange (Global Address List), an SMTP address is created. Basically, if someone send an email to that address, it'll be sent to all recipient in that list.
1) Is this by default in Exchange 5.5 ?
2) This is certainly a security issue. Why didn't spammers use it before?
3) Can I safely remove all email addresses (SMTP, CCMAIL, X400) from that list?