DNS Boot Camp

DNS is the heart of the Internet

The Domain Name System or DNS is central to the proper operation of the Internet as a whole and your email and web site specifically. It is responsible for resolving names such as email addresses and web site URLs to their proper IP addresses and vice-versa. DNS can even be used to help you reduce the amount of spam mail you receive by taking advantage of DNS-based black lists called RBLs, DNSBLs, and RHSBLs.

The biggest problem with DNS is the lack of knowledge about how to configure and manage it. The most highly-publicized example of this was on January 23, 2001 when Microsoft's entire Internet site was down for over a day due to their DNS servers being unreachable. Microsoft had no DNS redundancy.

Microsoft is not alone. At least 25% of all DNS servers today are broken in some way. Many of these broken servers are managed by Internet Service Providers (ISPs) who should know better. Even if your DNS is managed by someone else, it's in your best interest to know DNS so you can ensure the health of your Internet site.

The most popular implementation of DNS is the open source BIND package used by most DNS servers world-wide. Even proprietary vendor DNS servers, such as those from Microsoft and Novell are (mostly) compatible with BIND. However, BIND is a feature-packed, monolithic program that occassionally has security problems. Alternative DNS software is more secure and should seriously be considered for sites that wish to resist attacks.

This course focuses on BIND, djbdns, NSD, and Windows 2000 DNS. However, this knowledge is directly usable by people using other DNS software, such as Novell's DNS.

This course will bring you up to speed on DNS quickly. You'll understand the issues and keep your DNS running trouble free.

DNS Trainer

You'll receive a copy of the DNS trainer - a CD-ROM that allows you to use pre-installed, ready-to-run copies of the software covered in this course. You simply boot your computer from the CD-ROM. You don't need to install anything on your hard disk.

Course contents

Introduction: Overview of DNS; BIND 4, BIND 8, and BIND 9; Overview of BIND features; BIND on Unix, Linux, Windows and NetWare; Microsoft's DNS on NT/2000; Novell's DNS on NetWare 5
Domain Names: Upper level names; COM, EDU, GOV, INT, MIL, NATO, NET; Country names; The .US domain; The "dot" at the end of a name; Second level names; Lower level names
Registering Domain Names: ICANN-accredited registrars; Registering .US names; Registering domains in other countries; Registering DNS servers; Which contacts?; WHOIS databases
Setting up BIND: Master/Slave servers; Master file; Zone files; Setting up a master zone; Setting up a slave; Setting up forwarders
Resource Records: Address records; Mail Exchanger (MX) records; PTR records; SOH record; Setting the serial number; Setting Refresh and Retry times; Setting expiration times; The NOTIFY feature of BIND 8; SRV records; TXT records
DNS Tools: The nslookup program; The dig program; The host program; The dnswalk program
Logging: Channels and Categories; Using the Syslog facility; Logging queries; Lame server logging; Logging unapproved requests
Security: CERT DNS security advisories; Authorizing zone transfers; Authorizing queries; Version number reporting