Unbound is a validating, recursive, and caching DNS resolver that supports DNSSEC.

Install

Install the unbound package:

apk add unbound

Configure

The following configuration is an example of a caching name server (in a production server, it's recommended to adjust the access-control parameter to limit access to your network). The forward-zone(s) section will forward all DNS queries to the specified servers.

/etc/unbound/unbound.conf

server:
        verbosity: 1
        interface: 10.0.0.1
## To listen on all interfaces use the following line instead
#       interface: 0.0.0.0
        do-ip4: yes
        do-ip6: no
        do-udp: yes
        do-tcp: yes
        do-daemonize: yes
        access-control: 0.0.0.0/0 allow
## Other access control examples
#access-control: 192.168.1.0/24 action
## 'action' should be replaced by any one of:
#deny (drop message)
#refuse (polite error reply)
#allow (recursive ok)
#allow_snoop (recursive and nonrecursive ok).
python:
remote-control:
        control-enable: no
##enable to not answer id.server and hostname.bind queries. 
        hide-identity: yes
##enable to not answer version.server and version.bind queries. 
        hide-version: yes
## Note for forward zones, the destination servers must be able to handle recursion to other DNS server
## Forward all *.example.com queries to the server at 192.168.1.1
#forward-zone:
#        name: "example.com"
#        forward-addr: 192.168.1.1
## Forward all other queries to the Verizon DNS servers
forward-zone:      
        name: "."
# Level3 Verizon
        forward-addr: 4.2.2.1
        forward-addr: 4.2.2.4

Set auto-start, start and test the daemon

Set to auto-start then start unbound:

rc-update add unbound rc-service unbound start

Test:

dig nl.alpinelinux.org @10.0.0.1