問64
頻出度★★★
a～d のうち, ファイアウォールの設置によって実現できる事項として, 適切なものだけを全て挙げたものはどれか。 a 外部に公開する Web サーバやメールサーバを設置するための DMZ の構築 b 外部のネットワークから組織内部のネットワークへの不正アクセスの防止 c サーバルームの入り口に設置することによるアクセスを承認された人だけの入室 d 不特定多数のクライアントからの大量の要求を複数のサーバに動的に振り分けることによるサーバ負荷の分散
令和4年度 ITパスポート試験 問64
This question's explanation and your answers so far.
解説
問 64
- ア
正解 A firewall is a mechanism placed at the boundary between the internal network and the external network (the Internet) that permits or blocks the packets passing through it and thereby controls access. Item b, “preventing unauthorized access from an external network into the organization's internal area”, is precisely the central role of a firewall itself. Item a, the DMZ (demilitarized zone), is a configuration in which Web servers and mail servers made public to the outside are placed in a buffer area isolated from both the internal network and the outside; it can be built by using a firewall to separate the communication paths. Therefore, only the 2 items a and b can be achieved with a firewall, and the choice that lists only those, “ア (a, b)”, is the correct answer.
Incorrectイ
In addition to a and b, this also includes d, but the function in d, “dynamically distributing a large volume of requests across multiple servers to spread the load”, is the role of a load balancer (load-distribution device), not a function of a firewall. It is wrong because it includes the extra item d.
Incorrectウ
Item b is correct, but c, “restricting who can enter at the server room entrance”, is physical entry/exit control implemented by means such as IC cards or biometric authentication, which is a separate thing from a firewall that controls network communication. It is wrong because it drops item a (which a firewall can achieve) and includes the unrelated item c.
Incorrectエ
Neither c (physical entry/exit control) nor d (load distribution) is a function of a firewall. This includes none of the achievable items a and b and lists only the 2 items that a firewall cannot achieve, so it is wrong.
ここがポイント
- A firewall is a mechanism that controls access by permitting or blocking packets at the network boundary; preventing unauthorized access from outside and building a DMZ are its representative roles.
- Distinguish clearly that physical entry/exit control (access control) and load distribution (load balancer) are functions handled by mechanisms different from a firewall.
用語