Specifications

Additional Setup Options
BIG-IP® Reference Guide 12 - 9
In place of the <DNS_SERVER_1> parameter, use the IP address of a
properly configured name server that has access to the Internet. You can
specify additional name servers as backups by inserting an additional
nameserver line for each backup name server.
If you configure the BIG-IP itself as a DNS proxy server, then we suggest
that you choose its loopback address (127.0.0.1) as the first name server in
the /etc/resolv.conf file.
Replace the <DOMAIN_NAME_1> and <DOMAIN_NAME_2>
parameters with a list of domain names to use as defaults. The DNS uses
this list to resolve hosts when the connection uses only a host name, and not
an FQDN. When you enter domain names in this file, separate each domain
name with a space, as shown in Figure 12.3.
You can also configure the order in which name resolution checks are made
by configuring the /etc/irs.conf file. You should set this file so that it checks
the /etc/hosts file first, and then checks for DNS entries. See Figure 12.4,
for an example of how to make the entry in the /etc/irs.conf file.
Configuring DNS proxy
The BIG-IP is automatically configured as a DNS proxy or forwarder. This
is useful for providing DNS resolution for servers and other equipment load
balanced by the BIG-IP. This can be set in the Setup utility.
To re-configure DNS proxy, you simply edit the /etc/named.boot file that
contains these two lines:
forwarders <DNS_SERVERS>
options forward-only
In place of the <DNS_SERVERS> parameter, use the IP addresses of one
or more properly configured name servers that have access to the Internet.
You can also configure the BIG-IP to be an authoritative name server for
one or more domains. This is useful when DNS is needed in conjunction
with internal domain names and network addresses for the servers and other
equipment behind the BIG-IP. Refer to the BIND documentation for more
details.
; example /etc/resolv.conf
nameserver 127.0.0.1
nameserver 127.16.112.2 ;ip address of main DNS server
search mysite.com store.mysite.com
Figure 12.3 Sample /etc/resolv.conf file
hosts local continue
hosts dns
Figure 12.4 Sample entry for the /etc/irs.conf file