平成30年度秋期 ITパスポート試験問64

This question's explanation and your answers so far.

問64

頻出度★★★

プロキシサーバの役割として, 最も適切なものはどれか。

出典　平成30年度秋期 ITパスポート試験問64

解説

問 64

Incorrectア
“Managing the correspondence between domain names and IP addresses” is the role of a DNS (Domain Name System) server, not that of a proxy server.
イ
正解 A proxy server is a relay server that accesses Web servers and the like on the Internet on behalf of (as a proxy for) the PCs in an internal network. The internal PCs do not communicate with the outside directly; instead, they send requests to the proxy, and the proxy communicates with the outside and returns the results to the PCs. As a result, the internal PCs are not directly visible from the outside, and access control, content caching, and communication logging become possible. Therefore, choice イ, which states “connects to the Internet on behalf of the PCs within an internal network”, is the most appropriate.
Incorrectウ
“Assigning the PC the information required to connect to a network (IP address, subnet mask, default gateway, etc.)” is the role of a DHCP server, not that of a proxy server.
Incorrectエ
“Mutually converting between private IP addresses and global IP addresses” is a function of NAT (NAPT), which is usually handled by a router. It is not the role of a proxy server.

ここがポイント

A proxy server is a server that connects to and relays the external Internet as a “proxy” for internal PCs. It provides security and performance-enhancing functions such as access control, caching, and log collection.
Distinguishing the commonly confused servers and functions: DNS = managing the correspondence between names and IPs, DHCP = automatic assignment of connection information, NAT/NAPT = conversion between private and global IPs.

用語

解答問64イ