有个单机环境限制ssh登录，有多种方式，这里选择了配置hosts.allow和hosts.deny
root@db \~\]# more /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:172.100.100.56:allow sshd:172.100.100.57:allow sshd:172.100.100.42:allow sshd:172.100.100.43:allow sshd:172.100.100.46:allow \[root@db \~\]# 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 # sshd:all:deny \[root@db \~\]#