Recently, while driving to my work, I listened to radio as usual. Because of the establishment of the new EU (European Union) domain, there was an interview with a representative of one of the Internet Service Providers. For some time the interview went on, boringly similar to other common radio interviews, but suddenly the presswoman started to improvise and she asked, "But isn't the DNS too vulnerable? Is it prepared for terrorist attacks?" The ISP representative enthusiastically answered, "The whole Internet arose more than 30 years ago, initiated by the American Department of Defense. From the very beginning, the Internet architecture took into account that it should be able to keep the communication functional even if a part of the infrastructure of the USA were destroyed, i.e., it must be able to do without a destroyed area."
He went on enthusiastically, "We have 13 root name servers in total. Theoretically, only one is enough to provide the complete DNS function." At this point, we must stop for a moment our radio interview to remind you that a role and principle of usage of root name servers are described in the first chapter of this book. Now, let's go back to our interview again. The presswoman, not satisfied with the answer, asked, "All these root name servers are in the USA, aren't they? What will happen if someone or something cuts off the international connectivity, and I am not be able to reach any root name server?" The specialist, caught by the presswoman's questions, replied, "This would be a catastrophe. In such a case, the whole Internet would be out of order."
This publication is created to help beginners, who are already familiar with computers, to discover DNS secrets. It will be also useful for computer administrators and, specifically, for network administrators. It will be also useful as a textbook for DNS lectures.
This book discusses the fundamentals of DNS; it is not a manual for some concrete DNS implementation. It contains examples from both Windows and UNIX environments. It explains the DNS concepts to a user, independently of the hardware and software he or she uses. We can work effectively with DNS even in a not-so-powerful personal computer.
About the Authors
Libor Dostálek was born in 1957 in Prague, Europe. He graduated in mathematics at the Charles University in Prague. For the last 20 years he has been involved in ICT architecture and security. His experiences as the IT architect and the hostmaster of one of the first European Internet Service Providers have been used while writing this publication.
Later he became an IT architect of one of the first home banking applications fully based on the PKI architecture, and also an IT architect of one of the first GSM banking applications (mobile banking). As a head consultant, he designed the architecture of several European public certification service providers (certification authorities) and also many e-commerce and e-banking applications.
The public knows him either as an author of many publications about TCP/IP and security or as a teacher. He has taught at various schools as well as held various commercial courses. At present, he lectures on Cryptology at the Charles University in Prague. He is currently an employee of the Siemens.
Alena Kabelová was born in 1964 in Budweis, Europe. She graduated in ICT at the Economical University in Prague. She worked together with Libor Dostálek as a hostmaster. She is mostly involved in software development and teaching. At present, she works as a senior project manager at the PVT and focuses mainly on electronic banking. Her experiences as the hostmaster of an important European ISP are applied in this publication.