Which of the following programs uses the hosts.allow file to perform its main task of checking for access control restrictions to system services?
A.
tcpd
B.
inetd
C.
fingerd
D.
mountd
E.
xinetd
Explanation:
From the man pages:
The tcpd program can be set up to monitor incoming requests for telnet, finger, ftp, exec, rsh, rlogin, tftp, talk, comsat and other services that have a one-to-one mapping onto executable files. [..] There are two possible modes of operation: execution of tcpd before a service started by inetd, or linking a daemon with the libwrap shared library as documented in the hosts_access(3) manual page. Operation when started by inetd is as follows: whenever a request for service arrives, the inetd daemon is tricked into running the tcpd program instead of the desired server. tcpd logs the request and does some additional checks. When all is well, tcpd runs the appropriate server program and goes away.