我们知道，互联网上DNS服务器的事实标准就是ISC的BIND， Bill Manning对in-addr域的调查发现，有95%的域名服务器(2的2000次方个服务器中)使用的是各种版本的“bind”。这其中包括了所有的DNS根服务器，而这些根服务器对整个服务器的正常运转起着至关重要的作用。

    DNS服务面临的安全隐患主要包括：DNS欺骗（DNS Spoffing）、拒绝服务（Denial of service，DoS）攻击、分布式拒绝服务攻击和缓冲区漏洞溢出攻击（Buffer Overflow）。

 Options Clause

The options clause group together statements that have global scope - the statemnts apply to all zones or views unless overridden by the same statement in a view or zone clause. Only one options clause should be defined in a named.conf file. The options clause can take a serious list of statements.

options Clause Syntax

DNS BIND logging Clause

This section describes the logging clause which prior to BIND 9 needed to appear first in the named.conf file. This no longer the case and it may appear anywhere convenient. BIND uses syslogd before a valid logging clause is available so named.conf parse errors and other information will appear in /var/log/messages (depending on syslog.conf) prior to, or in the absence of, a valid logging clause. In the case of windows parse errors are written to the Event Log. Only one logging clause can be defined but multiple channels may be defined to stream logs.

         对于排除DNS故障来说，日志文件是极其重要的工具，DNS日志可以记录服务器CPU占用时间，查询统计信息以及配置中存在的问题。经常分析日志可以了解服务器的负荷，性能安全性，从而及时采取措施纠正错误。

Views in BIND 9

by Cricket Liu
05/14/2000

The view that computers on the Internet see is usually considerably stripped down from the internal version and only contains information about resources available on the Internet, including Web servers and mail servers. The internal view normally contains everything: all those hosts accessible from the Internet plus all those on the internal network.

Until recently, presenting one view of a zone to one community of hosts and another view to others has entailed running multiple sets of name servers or multiple name server processes on a single host in a tricky configuration. Nobody ever said being two-faced is easy.

BIND 9 introduced a new feature called "views" that makes delivering different versions of a zone, and even different name server configurations, easy. In this article, I'll describe how to use views to configure several two-faced name servers, each a little more complex than the last.