Brocade Communications Systems 12.4.00 Configuring the Gslb controller, Enabling DNS cache proxy

Basic GSLB for IPv6 configuration 2

Configuring the GSLB controller

The GSLB ServerIron ADX supports global server load balancing in DNS cache proxy with DNS override mode. In this mode, the GSLB controller responds directly to DNS queries with the “best” address, from a configured list of addresses, at the top of the DNS response.

When you enable the DNS override feature, you need to configure an IP list for the required domains. The ServerIron ADX performs health checks on the IP addresses configured for the domains and directly responds to client queries by using the GSLB policy to select the best IP address from the IP list configured for the requested domain.

NOTE

Although you do not need a real DNS server when you combine DNS cache proxy with DNS override, you still need to configure a virtual IP address for the DNS server. Clients send queries to the virtual IP address.

Adding a VIP for the ADNS server

The server virtual-name-or-ipcommand enables you to define a virtual server port on the GSLB ServerIron ADX. The virtual server acts as the authoritative DNS server (ADNS) for a domain. Clients send queries to the virtual IP address.

The ADNS VIP intercepts DNS requests for the domains configured on it. If the query is of type AAAA, then it performs global server load balancing in accordance with the configured GSLB policy on all IPv6 domain IP addresses for the requested domain and places the best IPv6 address at the top of the response.The ADNS VIP can be either an IPv4 or an IPv6 address.

To define an IPv6 intercept VIP on the GSLB ServerIron ADX, enter commands such as the following:

ServerIronADX(config)# server virtual-name-or-ip dns6-vip 2001:DB8::200 ServerIronADX(config-vs-dns-proxy)# port dns

The command in this example adds a virtual server called “dns6-vip” with the IP address 2001:DB8::200. The GSLB ServerIron ADX processes all client queries sent to this address. This command changes the CLI to the Virtual Server configuration level. At this level, the port dns command adds the DNS port to the virtual server.

Syntax: [no] server virtual-name-or-ip <name> [<ipv4-address> <ipv6-address]

The <name> parameter specifies the name for for the virutal server. The <ipv4-address> and <ipv6-address> parameters specify the respective IPv4 or IPv6 address of the virtual server.

Enabling DNS cache proxy

The dns cache-proxycommand enables you to configure the GSLB ServerIron ADX to act as a proxy for the authoritative DNS (itself a virtual server configured on the controller) so that the GSLB ServerIron ADX responds directly to the client queries.

To enable DNS cache proxy, enter the following commands:

ServerIronADX(config)# gslb policy

ServerIronADX(config-gslb-policy)# dns cache-proxy

Syntax: [no] dns cache-proxy

ServerIron ADX Global Server Load Balancing Guide	197
53-1002437-01