BIG-IP Global Traffic Manager (GTM) load balances incoming wide IP traffic to your network resources. BIG-IP GTM can work in conjunction with an existing DNS server on your network. In this situation, you configure the DNS server to delegate wide IP-related requests to the BIG-IP GTM for name resolution.
This implementation focuses on the fictional company SiteRequest, which recently purchased BIG-IP GTM to help load balance traffic across two of its web-based applications: store.siterequest.com and checkout.siterequest.com. These applications are delegated zones of www.siterequest.com, which an existing DNS server manages. They have already configured BIG-IP GTM with two wide IPs, store.wip.siterequest.com and checkout.wip.siterequest.com, which correspond to these two web applications.
Listeners control how BIG-IP GTM handles network traffic. A listener is a specialized virtual server that is assigned a specific IP address. A wildcard listener is a special listener that is assigned an IP address of 0.0.0.0 and DNS query port (port 53). When traffic is sent to the IP address of a listener, BIG-IP GTM either handles the traffic locally or sends the traffic to the appropriate resource.
Perform these tasks to delegate DNS traffic to wide IPs.
If you are unfamiliar with how to modify the files on DNS servers, review the fifth edition of DNS and BIND, available from O’Reilly Media.
Determine which DNS servers will delegate wide IP-related requests to BIG-IP GTM.
You now have an implementation of BIG-IP GTM in which a DNS server manages DNS traffic unless a query is for a wide IP configured on BIG-IP GTM. When the DNS server receives queries for store.siterequest.com or checkout.siterequest.com, it delegates the queries to BIG-IP GTM, which then load balances the traffic to the appropriate wide IPs.