Brocade Communications Systems ServerIron ADX 12.4.00 Manual Manual page 46

1
Configuring GSLB protocol parameters
When you enable DNS override, the GSLB ServerIron ADX replaces the IP addresses in the DNS
reply with the "best" of the proxy server addresses you specify. The GSLB ServerIron ADX
determines which proxy server IP address is the best using the GSLB policy metrics. For information
about the metrics, refer to
NOTE
DNS override is a global parameter but a list of proxy IP addresses are associated with a specific
host in a specific domain. If there are no proxy addresses for a given host, the GSLB ServerIron ADX
sends the DNS reply unaltered. An exception is if you have enabled the active only feature, in which
case the reply contains only the active addresses. Refer to
a health check"
To display the DNS override state, enter the show gslb policy command. The state is shown in the
DNS override field. Refer to
To display information about the IP addresses selected for a specific domain and host, enter the 
show gslb dns zone command. Refer to
Changing the GSLB policy metrics
"GSLB policy"
IP addresses in the DNS replies from the DNS server for which the ServerIron ADX is configured as
a proxy. You can change the policy by changing or deleting individual metrics.
policy metrics. The metrics are listed in their default order. The metric described in the first row is
the first metric the GSLB ServerIron ADX uses by default, and so on.
For example, you can change the following:
•
•
•
•
•
•
NOTE
If the GSLB policy rejects all of the sites, the GSLB ServerIron ADX sends the DNS reply unchanged
to the client.
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"GSLB policy"
on page 31.
"Displaying the default GSLB policy"
on page 6 describes the default policy the GSLB ServerIron ADX uses to evaluate the
Metric processing order: you can change the order in which the metrics are applied.
Metric state: you can disable or re-enable some metrics.
Session-table capacity and threshold tolerance: you can modify the values for these metrics.
FlashBack tolerance: you can modify the value for this metric.
RTT values: you can individually modify the cache interval, cache prefix, tolerance, and explore
percentage.
Connection load parameters: you can adjust the number of data collection intervals and the
relative weights given to the intervals.
on page 6.
"Removing IP addresses for sites that fail
on page 175 for more information.
"Displaying DNS zone and hosts"
ServerIron ADX Global Server Load Balancing Guide
on page 170.
Table 2 lists the GSLB
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