Maintaining the root.hints File
In Chapter 2 I alluded to the limited lifetime of a "root.hints" file. The set of rootservers and their addresses does change over time, albeit slowly. New ones are added, old ones retired, or moved—in a very conservative manner. The "powers that be" of DNS knows their responsibility. There are several ways to keep a root.hints file up-to-date, an updated version can be FTPed from a host, or DNS itself can be examined to determine if anything has changed—all automatically if you want. The quickest and easiest way is to use dig. First ask your own nameserver which root nameservers it thinks exist.
$ dig @127.0.0.1 . NS … ;; ANSWER SECTION: . 5d23h56m30s IN NS F.ROOT-SERVERS.NET. … . 5d23h56m30s IN NS H.ROOT-SERVERS.NET. ...Get Concise Guide to DNS and BIND, The now with the O’Reilly learning platform.
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