Geographic region for a prefix | 1 |
In the above example, with host policy “test” applied to host “www” for gslb1.com, when the ServerIron ADX receives client queries for www.gslb1.com, the GSLB ServerIron ADX returns only the healthy IP addresses with the best IP address at the top of the list (i.e., 1.1.1.101 only).
Since the global GSLB policy is in effect for host "ftp" for gslb1.com, when the ServerIron ADX receives client queries for ftp.gslb1.com, the GSLB ServerIron ADX will return all IP addresses for this domain with the best IP address at the top of the list (i.e., it returns 1.1.1.78 and 1.1.1.76).
Geographic region for a prefix
Brocade ServerIron ADX GSLB policies use a number of metrics, including the geographic location of a server, to evaluate the server IP addresses in a DNS reply.
The GSLB ServerIron ADX uses the Internet Assigned Numbers Authority’s (IANA’s) IP address prefixes (IPv4 or IPv6) to generate an initial static database of geographic prefixes. This database consists of IP address prefixes (IP address/prefix length) and their corresponding geographic locations, such as, the continent for each IP address prefix.
You can configure the geographic locations for an IP address prefix, or override an existing geographic region for an IP address prefix by configuring a new one. You can assign one of the following geographic locations to an IP address prefix:
•North America
•South America
•Europe
•Asia
•Africa
How geographic location is determined
Once you configure a geographic region for an IP address prefix, the GSLB ServerIron ADX determines the geographic region of a server in the following ways:
•For a real IPv4 or IPv6 address, the geographic region is based on the IP address. If you configure a geographic prefix that matches the real server IP address, the device obtains the geographic location of the real server from the geographic prefix entry that you configure.
•For a virtual IP address— a logical IP address configured on a site ServerIron ADX, the geographic region is based on the management IP address of the site ServerIron ADX on which the VIP is configured. If you configure a geographic prefix that matches the management IP address of the site ServerIron ADX on which the VIP is configured, the device obtains the geographic location of the VIP from the geographic prefix entry that you configure.
•If the management IP address of the remote ServerIron ADX at that site is not indicative of the geographic location, use the
For example, if the management IP address is in a private subnet, the address is not indicative of the ServerIron ADX’s geographic location. If you specify the region for the GSLB site, the GSLB ServerIron ADX uses the region you specify instead of the region of the ServerIron ADX’s
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