ll /etc/pam.d/
ll /etc/security
ll /lib64/security/*.so
ldd /usr/sbin/sshd
ldd `which sshd` | grep pam

yum install bind bind-utils
 dig -t soa www.baidu.com
 dig -t ns www.baidu.com
 dig -t a www.baidu.com

SOA
MX
NS
A
PTR
AAAA
CNAME

apt install bind9 bind9-utils

vim /etc/named
vim /etc/named.rfc1912.zones
vim /var/named/wang.org.zone
vim /var/named/1.0.1.zone

chown named.named wang.org.zone
chown named.named 1.0.1.zone

rndc reload

dig
nslookup
host

主从
子域委派
缓存
视图