The IB-4030 and IB-4030-10GE are high-performance DNS caching-only name servers. Using DNS cache acceleration services, can make DNS query resolution more responsive for resolvers across the network. These appliances can be part of an Infoblox Grid or operated independent DNS-caching appliances. The IB-4030 and IB-4030-10GE appliances support DNS queries on the LAN1, LAN2, MGMT, and HA ports.

Supported DNS Cache Acceleration Appliances

Following hardware appliances support software-based DNS Cache Acceleration:

• IB 22x5 series
• IB 40x5 series
• IB-4030 and IB-4030-10GE (Not supported from NIOS 9.0 onwards)

Following virtual appliances support software-based DNS Cache Acceleration:

• IB v22x5
• IB v40x5
• IB-FLEX
  

IB-4030 / IB-4030-10GE  implementation

The following figure illustrates the basic implementation of IB-4030 or IB-4030-10GE. In the figure, the network uses IB-4030 or IB-4030-10GE in an optimized deployment through the LAN1, LAN2, and MGMT ports, in which the appliance caches DNS responses for the intranet and for resolvers on the internet. The IB-4030 or IB-4030-10GE operates as a member of the Infoblox Grid, and responds to DNS requests from its cache, by doing this the appliance offloads that work from the authoritative servers. DNS requests, whose responses are not currently cached, are passed on to the authoritative servers, and their responses are returned to and cached by IB-4030 or IB-4030-10GE.

The DNS resource records are kept in the appliance's cache until they expire. The appliance uses the cache pre-fetch option to detect cached records that are about to expire and to fetch another copy before the records expire. When a query asks for cached data, in addition to returning the data, the appliance fetches a fresh copy from the authoritative server if the pre-fetch condition (configured through the Eligible and Trigger settings) is met. This option helps minimize the period of time, when no answer is available in the cache. The pre-fetch option is controlled by the following parameters:

• Eligible: The records that arrive with a TTL greater than the eligible value is considered for pre-fetch. The default value is 9 seconds.
• Trigger: This is the TTL value at which pre-fetch takes place. The default value is 2 seconds.

The pre-fetch option is enabled by default. Configuring of the Eligible and Trigger  is not supported at this time but might be supported in a future release.

Figure 1. Installation of the IB-4030 or IB-4030-10GE Grid 

Independent Appliance

You can deploy IB-4030 or IB-4030-10GE as an independent Infoblox appliance:

The following figure illustrates a simplified example of IB-4030 or IB-4030-10GE as an Independent Appliance.

Figure 2. IB-4030 or IB-4030-10GE deployed as an Independent Appliance

HA Configuration

To form an HA pair, you can deploy two IB-4030 or IB-4030-10GE appliances, as shown in the following figure. Only the active node in an HA pair handles DNS traffic; the passive node in standby mode and ready to take over if a failover occurs. During a failover, the passive node builds up the DNS cache over time and does not operate with preloaded cache or hot cache. From NIOS 8.6.x onwards, hybrid HA is supported. A hybrid HA pair can comprise a physical appliance and a virtual appliance, two physical appliances, or two virtual appliances. For more information on limitations of using HA pair combinations, see Limitations of Using a Combination of a Physical Appliance and a Virtual Appliance for HA.

Figure 3. IB-4030 or IB-4030-10GE as an HA pair