Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) User Manual
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Brocade Virtual ADX Global Server Load Balancing Guide
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Configuring GSLB protocol parameters
1
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 Brocade Virtual 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
Brocade Virtual ADX, there must be a set of IP addresses configured for the domain. The GSLB
Brocade Virtual 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 Brocade Virtual 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 Brocade Virtual 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 Brocade Virtual ADX, enter commands such
as the following.
Syntax: host-info host-name ip-list {ipv4-address | ipv6-address
The host-name parameter specifies the host name.
The ip-list ipv4-address and ipv6-address variables specify the proxy IPv4 or IPv6 address(es). You
can specify as many proxy IP addresses as you need. If you specify multiple addresses, separate
each address with a space. Here is an example.
host-info www ip-list 10.157.23.59 10.157.23.60 10.157.23.61 10.142.33.6
For information about the other syntax for the host command, refer to
To enable DNS override, enter the following command. You must enable DNS override to allow the
Brocade Virtual ADX to insert the proxy IP address in the DNS reply.
Virtual ADX(config)#gslb policy
Virtual ADX(config-gslb-policy)#dns override
Syntax: [no] dns override
When you enable DNS override, the GSLB Brocade Virtual ADX replaces the IP addresses in the
DNS reply with the “best” of the proxy server addresses you specify. The GSLB Brocade Virtual ADX
determines which proxy server IP address is the best using the GSLB policy metrics. For information
about the metrics, refer to
Virtual ADX(config)#gslb dns zone brocade.com
Virtual ADX(config-gslb-dns-brocade.com)#host-info www http
Virtual ADX(config-gslb-dns-brocade.com)#host-info www ip-list 10.157.23.59