Applies To:

Show Versions Show Versions

Manual Chapter: Load Balancing Non-Wide IP DNS Traffic to a Pool of DNS Servers
Manual Chapter
Table of Contents   |   << Previous Chapter   |   Next Chapter >>

Overview: Screening and forwarding non-wide IP traffic to a pool of DNS servers

BIG-IP Global Traffic Manager (GTM) can function as a traffic screener in front of a pool of DNS servers. In this situation, BIG-IP GTM checks incoming DNS queries and if the query is for a wide IP, resolves the query. Otherwise, BIG-IP GTM forwards the DNS query to one of the servers in a pool of DNS servers, and that server handles the query.

Traffic flow when BIG-IP GTM screens traffic to a pool of DNS servers

About listeners

A listener is a specialized virtual server that uses port 53 and to which you assign a specific IP address. When traffic is sent to that IP address, the listener alerts BIG-IP GTM and the system either handles the traffic locally or forwards the traffic to the appropriate resource.

You control how BIG-IP GTM responds to network traffic on a per-listener basis. The number of listeners you create depends on your network configuration and the destinations to which you want to send specific DNS requests. For example, a single BIG-IP GTM can be the primary authoritative server for one domain, while forwarding other DNS requests to a different DNS server. Regardless of how many listeners you configure, BIG-IP GTM always manages and responds to requests for the wide IPs that you have configured on the system.

Task summary

Perform these tasks to screen non-wide IP traffic and forward the traffic to a pool of DNS servers.

Creating a pool of local DNS servers

Gather the IP addresses of the DNS servers that you want to include in a pool to which BIG-IP GTM load balances DNS traffic.
  1. Log on to the command-line interface of BIG-IP GTM.
  2. Type tmsh, to access the Traffic Management Shell.
  3. Run a variation on this command sequence to create a pool using the IP addresses of the DNS servers on your network: create /ltm pool DNS_pool members add { 10.10.1.1:domain 10.10.1.2:domain 10.10.1.3:domain } monitor udp When you run the above example command, the system creates a BIG-IP LTM pool named DNS_pool that includes three DNS servers with the following IP addresses 10.10.1.1, 10.10.1.2, and 10.10.1.3. A UDP monitor is assigned to the pool to determine the availability of the pool members.
  4. Run this command sequence to save the pool: save /sys config
  5. Run this command sequence to display the pool: list /ltm pool
  6. Verify that the pool is configured correctly.

Creating a listener that alerts GTM to DNS queries for a pool of DNS servers

Configure a listener that alerts BIG-IP GTM to DNS queries destined for DNS servers that are members of a pool.
  1. Log on to the command-line interface of BIG-IP GTM.
  2. Type tmsh, to access the Traffic Management Shell.
  3. Run this command sequence to create a listener: create /gtm listener DNS_listener address 192.168.5.10 ip-protocol udp pool DNS_pool translate-address enabled When you run the above example command, the system creates a listener named DNS_pool with an IP address of 192.168.5.10 that alerts BIG-IP GTM to queries destined for the members of DNS_pool.
  4. Run this command sequence to save the listener: save /sys config
  5. Run this command sequence to display the listener: list /gtm listener The system displays the new listener configuration.

Implementation result

You now have an implementation in which BIG-IP GTM receives DNS queries, handles wide IP requests, and forwards all other DNS queries to members of the pool of DNS servers.

Table of Contents   |   << Previous Chapter   |   Next Chapter >>

Was this resource helpful in solving your issue?




NOTE: Please do not provide personal information.



Incorrect answer. Please try again: Please enter the words to the right: Please enter the numbers you hear:

Additional Comments (optional)