12.2.2. Other Statement Types
12.2.2. Other Statement Types The following is a list of lesser used statement types available within named.conf : controls - Configures various security requirements necessary to use the rndc command to administer the named service. Refer to Section 12.4.1, "Configuring /etc/named.conf " to learn more about how the controls statement is structured and available options. key " <key-name> " - Defines a particular key by name. Keys are used to authenticate various actions, such as secure updates or the use of the rndc command. Two options are used with key : algorithm <algorithm-name> - The type of algorithm used, such as dsa or hmac-md5 . secret " <key-value> " - The encrypted key. Refer to Section 12.4.2, "Configuring /etc/rndc.conf " for instructions on how to write a key statement. logging - Allows for the use of multiple types of logs, called channels . By using the channel option within the logging statement, a customized type of log, with its own file name ( file ), size limit ( size ), versioning ( version ), and level of importance ( severity ), can be constructed. Once a customized channel has been defined, a category option is used to categorize the channel and begin logging when named is restarted. By default, named logs standard messages to the syslog daemon, which places them in /var/log/messages . This occurs because several standard channels are built into BIND with various severity levels, such as one that handles informational logging messages ( default_syslog ) and another that specifically handles debugging messages ( default_debug ). A default category, called default , uses the built-in channels to do normal logging without any special configuration. Customizing the logging process can be a very detailed process and is beyond the scope of this chapter. For information on creating custom BIND logs, refer to the BIND 9 Administrator Reference Manual referenced in Section 12.7.1, "Installed Documentation" . server - Specifies options that affect how named should respond to remote nameservers, especially in regards to notifications and zone transfers. The transfer-format option controls whether one resource record is sent with each message ( one-answer ) or multiple resource records are sent with each message ( many-answers ). While many-answers is more efficient, only newer BIND nameservers understand it. trusted-keys - Contains assorted public keys used for secure DNS (DNSSEC). Refer to Section 12.5.3, "Security" for more information concerning BIND security. view " <view-name> " - Creates special views depending upon which network the host querying the nameserver is on. This allows some hosts to receive one answer regarding a zone while other hosts receive totally different information. Alternatively, certain zones may only be made available to particular trusted hosts while non-trusted hosts can only make queries for other zones. Multiple views may be used, but their names must be unique. The match-clients option specifies the IP addresses that apply to a particular view. Any options statements may also be used within a view, overriding the global options already configured for named . Most view statements contain multiple zone statements that apply to the match-clients list. The order in which view statements are listed is important, as the first view statement that matches a particular client's IP address is used. Refer to Section 12.5.2, "Multiple Views" for more information about the view statement.