問題文
A firewall is deployed as a redundant pair. What has to be shared between the two units so that the exchanges that are open at the moment of a switch keep running?
選択肢
- The set of rules alone, because the unit that takes over treats a packet that matches a permitting rule as the opening packet of a fresh exchange
- The record of open exchanges, because the unit that takes over has to answer on behalf of the unit that stepped aside until every exchange written in that record has been closed by its own ends
- The record of open exchanges, because the unit that takes over compares each arriving packet against that record, then turns away a packet belonging to an exchange it holds no entry for
- The set of rules alone, because the unit that takes over rebuilds the record of open exchanges from those rules as soon as the first packet of each exchange arrives at the interface it watches