Brocade Network Advisor SAN + IP User Manual v12.1.0 - Manual (Page 1453)

Brocade Network Advisor SAN + IP User Manual 1405
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GSLB policy management
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e. Select the tie breaker method from the Tie Breaker list. This value is used in case multiple
addresses pass the policy criteria without one address emerging as the best choice:
• Least Response: Selects the address of the site that has been selected least often in
previous DNS responses.
Note: ADX-type products do not support the Least Response tie-breaker method.
• Round Robin: Selects the first IP address in the DNS response for the first client
request, then selects the next address for the next client request, and so on.
5. Provide the following additional information for Domain Name System (DNS) servers.
a. In the Check Interval field, indicate how often the GSLB ServerIron ADX product refreshes
its zone and host information with DNS servers.
b. Select the TTL check box if you want the ServerIron ADX product to modify the Time to Live
(TTL) value in DNS responses before sending the responses to the client DNS server.
c. If the TTL check box is selected, enter the number of seconds in the TTL Value field. The
GSLB ServerIron ADX product changes the time to live (TTL) in each DNS record in the DNS
responses before sending them to the client DNS server. If the TTL check box is not
selected, the ServerIron ADX product does not change the TTLs, regardless of the value in
this field.
d. Select the Active check box if you want the ServerIron ADX product to remove IP addresses
obtained from DNS replies that fail a health check. The ServerIron ADX product removes
these addresses as long as the DNS query contains at least one address that passes the
health check.
By default, the GSLB ServerIron ADX product retains the same number of IP addresses in
the DNS replies from the DNS server. The GSLB policy swaps the IP address on the top of
the list with the best address selected by the GSLB policy.
e. If you do not want the default behavior, select the Best only check box to allow the
ServerIron ADX product to remove all addresses except the one that the host-level GSLB
policy selects as the best address.
f. Select the Cache Proxy check box if you want the ServerIron ADX product to act as a proxy
for a DNS server, by responding directly to the client queries without forwarding them to
the DNS server.
g. Select the Transparent Intercept check box if you want the ServerIron ADX product to
either redirect or directly respond to client requests only for domains configured on the
ServerIron ADX product. If the domain name requested by the client is not configured on
the ServerIron ADX product, the query is forwarded to the DNS server without interception,
and the reply is untouched by GSLB.
h. Select the CNAME Detect check box if you want the ServerIron ADX product to apply GSLB
to Canonical Name (CNAME) records. A CNAME record refers to another domain name
instead of an IP address.
i. Select the Override check box if you want the ServerIron ADX product to replace the IP
address in the DNS reply with the IP address you configure for the proxy server.