BIND（Berkeley Internet Name Domain） 是一种广泛使用的 DNS 服务器软件，它具有高可配置性和扩展性。在 BIND 中，DNS 服务可以分为主服务器（Primary DNS Server）和辅助服务器（Secondary DNS Server）。辅助 DNS 服务器也被称为从服务器（Slave DNS Server），它们通过从主服务器同步数据来提供冗余和高可用性。
辅助 DNS 服务器的主要功能
数据冗余和高可用性：辅助服务器从主服务器获取区域数据（zone data），确保当主服务器不可用时，DNS 查询依然能够得到响应。这提高了整个 DNS 系统的可靠性和可用性。
负载均衡：通过分散 DNS 查询负载到多个服务器，辅助服务器有助于减轻主服务器的负载，提升服务响应速度。
防止单点故障：辅助服务器可以在主服务器发生故障时接管 DNS 服务，避免单点故障导致的服务中断。
数据同步：辅助服务器定期与主服务器同步数据，确保辅助服务器上的 DNS 记录与主服务器保持一致。这种同步通常通过 zone transfer（区域传输）来实现，常见的方式有全量传输（AXFR）和增量传输（IXFR）。
zone "lixiaohui.cn" IN { type slave; file "slaves/lixiaohui.cn.zone"; masters { 172.25.250.10; }; }; zone "250.25.172.in-addr.arpa" IN { type slave; file "slaves/lixiaohui.cn.ptr"; masters { 172.25.250.10; }; };
Aug 23 01:01:51 serverb.lab.example.com named[26633]: zone lixiaohui.cn/IN: Transfer started. Aug 23 01:01:51 serverb.lab.example.com named[26633]: transfer of 'lixiaohui.cn/IN' from 172.25.250.10#53: connected using 172.25.250.11#52091 Aug 23 01:01:51 serverb.lab.example.com named[26633]: zone lixiaohui.cn/IN: transferred serial 1 Aug 23 01:01:51 serverb.lab.example.com named[26633]: transfer of 'lixiaohui.cn/IN' from 172.25.250.10#53: Transfer status: success Aug 23 01:01:51 serverb.lab.example.com named[26633]: transfer of 'lixiaohui.cn/IN' from 172.25.250.10#53: Transfer completed: 1 messages, 9 records, 281 bytes, 0.002 secs (140500 bytes/sec) Aug 23 01:01:51 serverb.lab.example.com named[26633]: zone 250.25.172.in-addr.arpa/IN: Transfer started. Aug 23 01:01:51 serverb.lab.example.com named[26633]: transfer of '250.25.172.in-addr.arpa/IN' from 172.25.250.10#53: connected using 172.25.250.11#33001 Aug 23 01:01:51 serverb.lab.example.com named[26633]: zone 250.25.172.in-addr.arpa/IN: transferred serial 1 Aug 23 01:01:51 serverb.lab.example.com named[26633]: transfer of '250.25.172.in-addr.arpa/IN' from 172.25.250.10#53: Transfer status: success Aug 23 01:01:51 serverb.lab.example.com named[26633]: transfer of '250.25.172.in-addr.arpa/IN' from 172.25.250.10#53: Transfer completed: 1 messages, 5 records, 197 bytes, 0.001 secs (197000 bytes/sec) Aug 23 01:02:01 serverb.lab.example.com named[26633]: resolver priming query complete
查询辅助DNS服务器
1 2 3 4
[root@serverb ~]# ll /var/named/slaves/ total 8 -rw-r--r--. 1 named named 326 Aug 23 01:01 lixiaohui.cn.ptr -rw-r--r--. 1 named named 480 Aug 23 01:01 lixiaohui.cn.zone
[root@servera ~]# cd /var/named/ [root@servera named]# vim lixiaohui.cn.zone [root@servera named]# cat lixiaohui.cn.zone $TTL 1D lixiaohui.cn. IN SOA ns.lixiaohui.cn. 939958092.qq.com. ( 2 ; serial 1D ; refresh 1H ; retry 1W ; expire 3H ) ; minimum 1D IN NS ns.lixiaohui.cn. ns 1D IN A 172.25.250.10 lxh 30 IN A 192.168.8.100 lxh-2 30 IN A 192.168.8.100 30 IN AAAA 2001:db8:2020::5300 @ 20 IN MX 10 mail.lixiaohui.cn. mail 30 IN A 172.25.250.10 support.online 1H IN A 172.25.250.10
[root@serverb ~]# cd /var/named/slaves/ [root@serverb slaves]# cat lixiaohui.cn.zone $ORIGIN . $TTL 86400 ; 1 day lixiaohui.cn IN SOA ns.lixiaohui.cn. 939958092.qq.com. ( 2 ; serial 86400 ; refresh (1 day) 3600 ; retry (1 hour) 604800 ; expire (1 week) 10800 ; minimum (3 hours) ) NS ns.lixiaohui.cn. $TTL 20 ; 20 seconds MX 10 mail.lixiaohui.cn. $ORIGIN lixiaohui.cn. $TTL 30 ; 30 seconds lxh A 192.168.8.100 lxh-2 A 192.168.8.100 AAAA 2001:db8:2020::5300 mail A 172.25.250.10 $TTL 86400 ; 1 day ns A 172.25.250.10 $TTL 3600 ; 1 hour support.online A 172.25.250.10
确认日志消息正确
1 2 3 4 5 6 7
Aug 23 04:05:50 serverb.lab.example.com named[864]: client @0x7fe308044c90 172.25.250.10#53572: received notify for zone 'lixiaohui.cn' Aug 23 04:05:50 serverb.lab.example.com named[864]: zone lixiaohui.cn/IN: notify from 172.25.250.10#53572: serial 2 Aug 23 04:05:50 serverb.lab.example.com named[864]: zone lixiaohui.cn/IN: Transfer started. Aug 23 04:05:50 serverb.lab.example.com named[864]: transfer of 'lixiaohui.cn/IN' from 172.25.250.10#53: connected using 172.25.250.11#46605 Aug 23 04:05:50 serverb.lab.example.com named[864]: zone lixiaohui.cn/IN: transferred serial 2 Aug 23 04:05:50 serverb.lab.example.com named[864]: transfer of 'lixiaohui.cn/IN' from 172.25.250.10#53: Transfer status: success Aug 23 04:05:50 serverb.lab.example.com named[864]: transfer of 'lixiaohui.cn/IN' from 172.25.250.10#53: Transfer completed: 1 messages, 10 records, 289 bytes, 0.001 secs (289000 bytes/sec)
微信
