DNS Server Options for Linux

The first choice you must make when setting up a DNS server is which DNS server package to use. There are several options in Linux with varying capabilities. The most common packages include the following:

• BIND ” The Berkeley Internet Name Domain (BIND) is the most popular DNS server in Linux, and it's the one upon which this chapter focuses. BIND ships with all major Linux distributions, and its Web site is http://www.isc.org/products/BIND/. The current version as I write is 9.2.0, but in early 2002, many Linux distributions still ship with the older 8.2. x versions. The still older 4.9. x versions used a different configuration file format.

• djbdns ” D. J. Bernstein's DNS server is an alternative to BIND that's popular among some users. Originally known as tinydns , djbdns is designed to be smaller, more efficient, and more secure than BIND. It's not the standard DNS server for any distribution discussed in this book, but you can replace BIND with djbdns if you like. You can read more about djbdns at its Web page, http://cr.yp.to/djbdns.html.

• pdnsd ” This is a proxy DNS daemon. It's designed mainly for use on a local network as a proxy for a remote DNS server. It also supports limited local domain name resolution features, but it doesn't support the full range of features implemented by BIND or djbdns . You can read more at http://home.t-online.de/home/Moestl/.

• dnscache ” Like pdnsd , dnscache is a proxy DNS server; it's designed exclusively to speed up DNS lookups on a local network. Unlike pdnsd , dnscache provides no support for locally defined hosts , aside from localhost (127.0.0.1). The dnscache server is available from http://cr.yp.to/djbdns/dnscache.html.

Most Linux administrators who need to run DNS use BIND, because it ships with all major Linux distributions and is the most common DNS server. The security conscious sometimes pick djbdns because of its greater emphasis on security. Proxy DNS servers are often useful on small networks for local caching or even local name resolution, but they aren't good choices if you want to host your own domain and provide name resolution services to outside systems. The rest of this chapter focuses upon BIND, but some of the administrative tasks will be similar if you use djbdns .