Linux Server Security, Second Edition

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

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Chapter 6: Securing Domain Name Services (DNS)

The less common record types shown in Table 6-6 have no helper applications.

After making changes to a datafile, type

make. This runs the tinydns-data program to

convert data to data.cdb. The conversion will only overwrite the existing database if

the source data is consistent. tinydns will start serving the new data immediately.

Some tinydns-backed sites actually keep their zone data in databases (SQL or LDAP)

or separate files for ease of editing, and generate the tinydns datafile when needed.

Running djbdns client programs

In addition to its server daemons and support processes, djbdns includes client utili-

ties (Table 6-7). These perform the same functions as BIND’s old utilities, nslookup

and dig, and are useful for troubleshooting and testing your DNS infrastructure.

They work with any nameserver, not just tinydns.

add-alias fqdn ip +fqdn:ip:ttl:ts Specify an alias: create another A record (fqdn to ip).

add-mx fqdn ip @dom:ip:x:dist: ttl:ts Specify a mail server: create an MX record. If x contains

any dots, it is treated as a literal hostname; otherwise, it

is interpreted as

x.ns.dom. dist is distance and

defaults to

0.

Add-mx also generates sequential hostnames of

a, b,

etc. for

x.

Table 6-6. Less-common record types

Helper application ...