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Netra Proxy Cache Array Configuration Guide

Updating the DNS

After you finish installing your configuration to all hosts in your Netra Proxy Cache Array, you must update the DNS to make it aware of the existence of the subdomain formed by the array.

As you perform Netra Proxy Cache configuration, the configuration software collects data on your DNS configuration and creates a file in the /var/opt/SUNWscalr/dns directory called README.how_to_point_dns. The following is an example of such a file: 

; Please delegate the cache zone in your main dns to
; the dns server on the proxy cache appliance array. 
; To do this add the following to the appropriate db file 
cache 3600    IN NS dns.cache.acme.com.
dns.cache.acme.com.    3600    IN A a.b.c.50

To Update Your DNS

  1. From a machine not in the Netra Proxy Cache Array, use telnet to connect to the administrative host.

  2. Use ftp to copy README.how_to_point_dns to the /tmp directory of the DNS server that points to the Netra Proxy Cache Array.

  3. On the DNS server, copy the uncommented portion of the file README.how_to_point_dns to the database file.

  4. As root, enter a command such as the following: 

    {dns_server}# kill -HUP `cat /etc/named.pid`

Following this, clients can use the proxy cache service provided by the Netra Proxy Cache Array.

A Note on DNS Round Robin

For optimal operation of the array, the DNS server that resolves the name of the Netra Proxy Cache Array should support round robin. The default time-to-live (TTL) used by the DNS server in the array assumes round-robin support. With round robin, the array can respond to changes (including overloads and host failures) far more quickly than it can without round robin.

If your DNS server does not support round robin, you can reduce the TTL to a low value, such as 30 seconds. If your DNS server does not support a TTL as low as 30 seconds (for example, older DNS servers do not support TTL values of less than five minutes), it is recommended that you upgrade to a DNS server that supports round robin.

For support of round robin, the correct version of bind is 4.9.3 (or later). This version is shipped with Solaris 2.5.1 SHWP (the Solaris version shipped with the Netra Proxy Cache product) and is available in the following patches:

If your DNS server is a non-Solaris machine, you should upgrade that server to a 4.9.3 version of bind that has round-robin capability.

See Section 5.4 of the Netra Proxy Cache Array User's Manual for instructions on changing the DNS's TTL for the array.