Apéndice AN. Archivo de configuración /etc/hosts.deny

# /etc/hosts.deny: list of hosts that are _not_ allowed to access the system.
#                  See the manual pages hosts_access(5), hosts_options(5)
#                  and /usr/doc/netbase/portmapper.txt.gz
#
# Example:    ALL: some.host.name, .some.domain
#             ALL EXCEPT in.fingerd: other.host.name, .other.domain
#
# If you're going to protect the portmapper use the name "portmap" for the
# daemon name. Remember that you can only use the keyword "ALL" and IP
# addresses (NOT host or domain names) for the portmapper. See portmap(8)
# and /usr/doc/portmap/portmapper.txt.gz for further information.
#
# The PARANOID wildcard matches any host whose name does not match its
# address. You may wish to enable this to ensure any programs that don't
# validate looked up hostnames still leave understandable logs. In past
# versions of Debian this has been the default.
# ALL: PARANOID

# Desautorizar a todos los hosts con nombre sospechoso
ALL: PARANOID

# Desautorizar a todos los hosts
ALL:ALL