解决：etwork unreachable resolving问题

系统： CentOS Linux release 7.7.1908 (Core)
bind: BIND 9.11.4-P2-RedHat-9.11.4-16.P2.el7_8.6

部署使用bind后， 使用systemctl status named或者查看messages日志，都能看到
Jul 12 06:08:40 od-bind-81 named[994]: network unreachable resolving 'gateway/A/IN': 2001:500:12::d0d#53
Jul 12 06:08:40 od-bind-81 named[994]: network unreachable resolving 'gateway/A/IN': 2001:500:2::c#53
Jul 12 06:08:40 od-bind-81 named[994]: network unreachable resolving 'gateway/A/IN': 2001:dc3::35#53
的报错信息，
缘由：named尝试使用IPV6进行传输
因此让named只运行在IPV4模式下：
cat >> /etc/sysconfig/named <<EOF
OPTIONS="-4"
EOF

检查一下是否已经添加：
cat /etc/sysconfig/named

重启named
systemctl restart named

查看运行状况
systemctl status named

就没有报错信息了