Revision as of 21:16, 11 November 2013

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
## Specify the interface address to listen on:
        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 (sends  a  DNS  rcode REFUSED error message back)
#allow (recursive ok)
#allow_snoop (recursive and nonrecursive ok).
## Minimum lifetime of cache entries in seconds.  Default is 0.
#cache-min-ttl: 60
## Maximum lifetime of cached entries. Default is 86400 seconds (1  day).
#cache-max-ttl: 172800
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, for example:

dig nl.alpinelinux.org @10.0.0.1

or:

nslookup www.google.cz @10.0.0.1

or use drill, which requires the drill package:

drill www.bbc.co.uk @10.0.0.1

Further information

unbound.conf man page unbound optimization guide excellent unbound tutorial at calomel.org

@@ Line 49: / Line 49: @@
 forward-zone:
          name: "."
-# Level3 Verizon
+## Level3 Verizon
          forward-addr: 4.2.2.1
          forward-addr: 4.2.2.4</pre>
@@ Line 64: / Line 64: @@
 or use drill, which requires the {{Pkg|drill}} package:
 {{Cmd|drill www.bbc.co.uk @10.0.0.1}}
+= Further information =
+[http://linux.die.net/man/5/unbound.conf unbound.conf man page]
+[http://unbound.net/documentation/howto_optimise.html unbound optimization guide]
+[https://calomel.org/unbound_dns.html excellent unbound tutorial at calomel.org]
 [[Category:Networking]]