Recursive DNS Cache Service

This service has been discontinued on 2015-06-06 (News Article)

This DNS Cache Service is available only to users of SixXS address space. We are running (PowerDNS) recursor jobs on some of the SixXS PoPs. They allow access to all IPv6 netblocks of SixXS, both tunnel space as well as routed (subnet) delegations.

The Recursive DNS Caches can be found at:

nscache.eu.sixxs.net - Europe
nscache.us.sixxs.net - United States
nscache.ap.sixxs.net - Asia Pacific

Configuration

To set up your system to use this service, add one or more IPv6 addresses of the resolvers to /etc/resolv.conf (you can look them up by typing dig AAAA nscache.XX.sixxs.net or host -t AAAA nscache.XX.sixxs.net). And remember: the resolvers only answer queries that originate from IPv6 space allocated to the SixXS PoPs and our users (ie, not the general public). For latency reasons it's important to add the resolver of your continent. European users use eu, North American users use us and Asia Pacific users use ap (sorry, only one resolver there).

Windows XP

Windows XP unfortunately does not support IPv6 DNS servers directly. As a hackish work-around though one could install bind and point your local DNS resolver there.

Using a forwarding DNS server

If you already have a local caching/resursive DNS server you can also configure that to forward the queries to these DNS caches. In BIND one can accomplish this with a 'forwarders' statement in the options section.

AICCU (all platforms)

If you are an AICCU user, please keep in mind that in order for the client to set up your tunnel, it will have to do a DNS lookup for tic.sixxs.net, which will be impossible if you don't have IPv6 connectivity yet and when you have configured the above IPv6-only resolvers. We are working on a new version of AICCU which will be available to avoid this, and also solve some other outstanding issues.

Therefore, we recommend the use of our resolvers only if you have a statically configured tunnel.

Example Query

As a cool example, consider this query:

$ dig @nscache.eu.sixxs.net AAAA www.google.com

; <<>> DiG 9.4.2-P2 <<>> @nscache.eu.sixxs.net AAAA www.google.com
; (6 servers found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51932
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.google.com.			IN	AAAA

;; ANSWER SECTION:
www.google.com.		438162	IN	CNAME	www.l.google.com.
www.l.google.com.	243	IN	AAAA	2001:4860:a003::68

;; Query time: 58 msec
;; SERVER: 2001:1418:10:2::2#53(2001:1418:10:2::2)
;; WHEN: Wed Apr  1 19:44:36 2009
;; MSG SIZE  rcvd: 80

Questions, Answers and Comments

If you have any questions, feel free to contact SixXS. Please note that SixXS should be the first point of contact for any trouble with the resolvers. If you have difficulty accessing the nameservers, please open a ticket with us, or mail <info@sixxs.net>. If possible please include the full output from 'dig' as per the example above.

A note on DNS query logging / privacy

The SixXS Recursive DNS Cache Service does not log any queries neither do they manipulate queries nor answers. The caches are running standard PowerDNS instances with an allow-from-file option specifying the SixXS prefixes.