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 can be more responsive for resolvers across the network. The appliance These appliances can be part of an Infoblox Grid or operates as an operated independent DNS-caching applianceappliances. The IB-4030 and IB-4030-10GE appliances support DNS queries on the LAN1, LAN2, MGMT, and HA ports.

Supported DNS Cache Acceleration Appliances

...

• 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 a the basic implementation of the IB-4030 or IB-4030-10GE. In the following figure-, the network uses an IB-4030 or IB-4030-10GE appliance in an optimized deployment through the LAN1, LAN2, and MGMT ports, in which the appliance caches DNS responses for the Intranet intranet and for resolvers in on the Internetinternet. The IB-4030 or IB-4030-10GE operates as a member of the Infoblox Grid, and responds to DNS requests from its cache, offloading 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 the IB-4030 or IB-4030-10GE appliance.

The DNS resource records are kept in its 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 actual expirationthe records expire. When a query asks for cached data that has been cached, 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 time window in which 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 are is considered for pre-fetch. The default value is 9 seconds.
• Trigger – The : 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 and currently you cannot configure . Configuring of the Eligible and Trigger values. Configuration for these values   is not supported at this time but might be supported in a future releasesrelease.

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

Independent Appliance

You can deploy the IB-4030 or IB-4030-10GE as an independent Infoblox appliance. A simplified example of which is shown in the following figure:

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 as deployed as an Independent Appliance

HA Configuration

You To form an HA pair, you can deploy two IB-4030 or IB-4030-10GE appliances of the same model to form an HA pair, as shown in the following figure. Note that only Only the active node in an HA pair handles DNS traffic. The ; the passive node is in a standby mode and ready to take over if a failover occurs. Note that During a failover, the passive node builds up the DNS cache over time and does not operate with a pre-loaded preloaded cache or hot cache during a failover; it builds up the DNS cache over time. For information about how to configure an HA pair, refer to the NIOS documentation at docs.infoblox.com.. 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 Pairpair