Under normal circumstances, the Emai1 protocols we often talk about include ____, POP3, and SMTP.[fill in the blank]*

If users on the external network (where the security zone is Untrust) are allowed to access the intranet server (where the security zone is DMZ), the destination security zone selected when configuring the security policy is ________.

The repair of anti-virus software only needs to repair some system files that were accidentally deleted when scanning and killing viruses to prevent the system from crashing

Which items are the encryption techniques used by digital envelopes? (Multiple Choice)

"Implement security monitoring and management of information and information systems to prevent illegal use of information and information systems", in order to achieve which feature in information security?