[root@localhost ~]# cat /etc/hosts.allow
#
# hosts.allow This file contains access rules which are used to
# allow or deny connections to network services that
# either use the tcp_wrappers library or that have been
# started through a tcp_wrappers-enabled xinetd.
#
# See \'man 5 hosts_options\' and \'man 5 hosts_access\'
# for information on rule syntax.
# See \'man tcpd\' for information on tcp_wrappers
#
sshd:192.168.27.39/255.255.255.0:allow
[root@localhost ~]# cat /etc/hosts.deny
#
# hosts.deny This file contains access rules which are used to
# deny connections to network services that either use
# the tcp_wrappers library or that have been
# started through a tcp_wrappers-enabled xinetd.
#
# The rules in this file can also be set up in
# /etc/hosts.allow with a \'deny\' option instead.
#
# See \'man 5 hosts_options\' and \'man 5 hosts_access\'
# for information on rule syntax.
# See \'man tcpd\' for information on tcp_wrappers
#
这样就只能从192.168.27.39这台机器登陆服务器了。
sshd:ALL:deny