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Network Services—Internet ServersCaching forwarder: In this mode, BIND does not have any name to address mappinginformation locally, and it forwards DNS requests to specified upstream DNS servers(or root DNS servers) to find out the answer, and caches the answer after sending theresponse to the client.While it is possible to run the DNS server in a mixed mode (authoritativeand forwarding simultaneously), it is not advisable to do so.Forwarding/Caching DNS ServerThis is the case that is used on a LAN or service provider environment to provideusers with faster DNS responses and lower upstream network overhead.To set up a DNS forwarder on FreeBSD 7, first, you need to enable BIND by addingthe following variable to the /etc/rc.conf file as shown here:named_enable="YES"And start the server manually, as shown here:# /etc/rc.d/named startSince you have not defined any zone information, the server is running inforwarding mode. By default, the server listens on localhost (127.0.0.1) so that theclients on your network will not be able to communicate with the server. You needto edit the bind configuration file located at /etc/namedb/named.conf to removethis restriction. You can comment out the following line to completely disable thisrestriction, or modify it based on your network configuration to have the named(8)daemon listen on the IP address you have specified:listen-on { 127.0.0.1; };Once you have removed or modified the configuration, you should restart thenamed(8) daemon for changes take effect:# /etc/rc.d/named restartIn this mode, the named daemon contacts the ROOT DNS servers (as defined in/etc/namedb/named.root file) and then other DNS servers, recursively, to resolveincoming requests, and caches the results for later reference. This can slow thingsdown although you always get the authoritative and accurate result.[ 216 ]