Linux, Unix, /etc

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Review of Getting Connected:The Internet at 56K and Up

"Getting Connected" is, as the subtitle implies, a book for those who want an Internet connection that is more ambitious than the ubiquitous modem plus dial-up account with your friendly local Internet Service Provider (ISP). It deals in the often murky waters of dedicated connections to the Internet.

The book begins with an examination of the various decisions which need to be made before any work starts on the link itself. Help is given in calculating your bandwidth requirements - a good guide to what often seems like a black art; and in figuring out overall costs.

Moving on to the technical meat of the book, the discussion of routers is particularly clear and helpful. It gives useful practical examples of access lists, and filtering. This is noteworthy, as few publications deal with this important area in any detail; thus, implementors are frequently left to the tender mercies of the vendor's manual.

The mandatory explanation of networking layers follows, a brief but clear overview of IP on an Ethernet LAN. The various types of physical connection, such as the traditional leased line, ISDN, etc, are examined; as are the data link protocols available, chapters being devoted to PPP and SLIP, Frame Relay, X.25, ATM, and SMDS and HDLC.

The subject of firewalls, an important consideration for any company connecting to the Internet, is given a concise but thorough examination in the chapter on "Internet Security". Once again, with skimping on the theory, Dowd is very strong on practical advice and examples.

The introduction to DNS is very good. The book provides the basic information necessary to set up name service, both for a simple internet host and for a firewall.

Chapter 18, on "Internet Mail", is a good practical course in using sendmail to interface the local LAN mail systems to the big bad Internet. Enough detail is given of the fearsome sendmail.cf configuration file to allow the attentive reader to make simple changes to their sendmail setup. The chapter focuses on the use of a Unix server as a "plug-in" unit, providing mail services to the rest of the LAN. This is a wise emphasis. Many people connecting to the Internet for the first time try to use the main file server, particularly on small networks, as the Internet host as well. Where the file server OS is not Unix, this is not wise; even where it is, the advantages of a separate Internet host are manifold, not least the added security this gives.

"IP on the Desktop" is an admirably concise overview of the TCP/IP connectivity options for the common desktop OSs in commercial IT.

A brief overview of various Internet services - e-mail, Usenet, WWW - is spread over a number of appendices, and enough information is given there to get started with.

Overall, the book is very strong on practical problems and solutions to them. it covers well all the steps from initial planning to configuring internet services. It is particularly strong on DNS, firewalls and e-mail; but it is difficult to find fault with any aspect of the book. A very worthwhile purchase for anyone involved in linking to the Internet. The administrator of even a humble dial-up line will find much relevant information here; for someone with a fixed link, it is invaluable. As a source book for anyone considering implementing such a link, it is invaluable.

Getting Connected:The Internet at 56K and Up
Kevin Dowd
O'Reilly
June 1996
410 pages
$29.95

Check my Amazon marketplace — I might have a copy of this book for sale.

Paul Dunne 1996

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