2.4 BIND9

vENUM MP uses BIND9 as a Domain Name Server for interacting with the Domain Name System (DNS) clients.

BIND is a suite of software for interacting with DNS. It acts as an authoritative name server for configured DNS zones and a recursive resolver in the network.

BIND9 facilitates the following functions:

Access Control

Access Control Lists (ACLs) are the address match lists that give users control over who can access the name server. These are configured in the following two categories:

• Allowed
• Blocked

The Blocked ACLs take precedence over allowed ACLs.

Forwarding ENUM queries to vENUM application

If the incoming DNS query is for an E164 number (that is ENUM query), then it if forwarded by Bind9 server to one of the available vENUM applications. The e164.arpa zone is the default zone configured in the Bind9 DNS server. More ENUM type zones can be added with Zone type as ENUM in DNS Zone Config MO. For further information, refer to the DNS Zone Config section.

Caching

BIND9 caches the responses through specified TTL. For ENUM queries, it uses the TTL configured in EnumOptions MO and for the non-ENUM DNS queries, it uses TTL defined in Zone and DNS Record. The advantages of caching responses are:

• Improvement in application performance
• Reduction in the load on the backend
• Reduction of database cost
• Elimination of database hotspots

Note:

Due to caching, responses received from ENUM zones might be stale if the TTL is not set to 0 in ENUM Options table.