Configuring GSLB protocol parameters | 1 |
Syntax: [no] dns ttl
Enabling DNS override
By default, the GSLB ServerIron ADX selects the best site IP address from among the addresses contained in the DNS reply. You can override the DNS reply for an individual domain (zone plus a host) by specifying a list of IP addresses, then enabling DNS override. The GSLB controller replies with all available IP addresses for the respective domain with best IP address on top of the list.
DNS override is useful when you want to provide the best address for a web proxy without the need to configure the proxy’s IP address onto the DNS server itself.
DNS override is a global parameter. You configure redirection on an individual host basis, then globally enable the GSLB ServerIron ADX to replace the IP addresses in the DNS reply with the proxy server addresses you configure.
Once you configure DNS override, for each domain name (zone and host) configured on the GSLB ServerIron ADX, there must be a set of IP addresses configured for the domain. The GSLB ServerIron ADX replaces the IP addresses in a DNS response with the best choice (only the best choice) from the set of configured IP addresses. If a domain name does not have a configured address, the ServerIron ADX sends the DNS reply unaltered to the client.
NOTE
The host and its associated health check (if applicable) must be configured before you configure the IP address list.
You can specify as many proxy server IP addresses as you need for a given domain. When you specify multiple proxy server addresses, the ServerIron ADX uses the applicable GSLB policy metrics to select the best address from the list of addresses you configure and places that address in the DNS reply.
To configure the proxy server information on the GSLB ServerIron ADX, enter commands such as the following:
ServerIronADX(config)# gslb dns zone brocade.com
Syntax: host-info <host-name> ip-list {<ipv4-address> <ipv6-address>
The
The
For information about the other syntax for the host command, refer to “Configuring a zone” on page 21.
To enable DNS override, enter the following command. You must enable DNS override to allow the ServerIron ADX to insert the proxy IP address in the DNS reply.
ServerIronADX(config)# gslb policy
Syntax: [no] dns override
ServerIron ADX Global Server Load Balancing Guide | 33 |
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