A sample chapter from O'Reilly's DNS and Bind book describes optional security features of the DNS and how to use them. World wide web Web servers are commonly defaced by those who wish to publish their own opinions. Well-known security problems make this much easier than it should be. It is, of course, embarassing to have your own publicity material replaced by someone else's. There have also been instances of sensitive material being stolen from compromised web servers.
Many problems arise from insecure scripts installed on web servers .
Unneeded scripts should always be removed and others installed only once you are confident that you understand the risk they represent. Proxy servers Proxy servers are commonly used as a gateway between an organisational network and the Internet. The most common examples are MS Proxy and the Squid web cache. Proxies may be used to isolate local hosts from the Internet, for example when using private IP address ranges, to enforce local policies or to provide improved service. Problems can arise with proxies if, instead of acting as a gateway between local users and remote sites, they can be used by remote users to access remote sites.