Installing and Administering Internet Services

Chapter 3 99

Conﬁguring and Administering the BIND Name Service

Conﬁguring a Primary Master Name Server

Forwarding Options: The forwarding facility can be used to create a

large site-wide cache on a few servers, reducing trafﬁc over links to

external name servers. It can also be used to allow queries by servers

that do not have direct access to the Internet, but wish to look up

exterior name anyway. Forwarding occurs only on the queries for which

the server is not authoritative and does not have the answer in its cache.

Name Checking Option: The server can check domain names based

on their expected client contexts. For example, a domain name that is

notify yes_or_no; The default is yes. When set to yes, DNS NOTIFY

messages are sent when a zone for which the server is

authorized changes. The use of NOTIFY speeds

convergence between the master and its slaves. A slave

server that received a NOTIFY message and understands

it will contact the master server for the zone and see if a

zone transfer is needed. If this is the case, the slave

server will initiate the zone transfer immediately. The

notify option may also be speciﬁed in the zone statement,

in which case, it overrides the options notify statement.

recursion yes_or_no; If this is yes, a DNS query requests recursion, then the

server will attempt to do all the work required to answer

the query. If this is no, then recursion is not on, the

server will return a referral to the client if it doesn’t know

the answer. The default is yes.

Table 3-4 Boolean Options

Option Description

Table 3-5 Forwarding Options

Option Description

forward (only | first); This option is only meaningful if the forwarders list is

not empty. The default value is first. When first is

speciﬁed, the server queries the forwarders ﬁrst. If

only is speciﬁed, the server will query only the

forwarders.

forwarders { [ in_addr ; [

in_addr ; . . . ] ] };

This speciﬁes the IP addresses to be used for

forwarding. The default is empty list or no forwarding.