In the construction of information security system, it is necessary to accurately describe the relationship between important aspects of security and system behavior through security models.

Which of the following is the default backup mode of dual-machine hot backup?

At this stage, we have mastered three source NAT technologies, namely NAT No-PAT and ______ Easy IP.

When the company's network administrator is performing dual-system hot backup, due to the possibility of inconsistent round-trip paths, if he wants to enable the session fast backup function, the command that needs to be entered is ______[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 ________.