How to request a reverse DNS delegation for a /48 IPv6 prefix ?


Reverse DNS allows host to map IP addresses to hostnames. For example 3ffe:b00:c18:1::666 maps
to To test this you can do the following query :


dig ptr

You should see the following output:


;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 3


;;, type = PTR, class = IN




In the DNS world, Reverse DNS uses PTR records to store hostnames related IP addresses.

With the TSP IPv6 over IPv4 profile tunnel owners can assign an external DNS that will answer reverse
DNS queries for their /48 prefix.

This document does not explain how to setup a DNS server. It explains how you can configure your
existing DNS server to answer DNS queries for your prefix.

If you don't know how to manage a DNS server we strongly recommend that you do not to use this feature.

Reverse DNS setup

1. Download the latest client
Available in the download page.

2. Create a new zone file for your prefix

Here's an example with a fictious prefix and dns server :
Fictious prefix is 3ffe:b80:1234::/48
Fictious dns server is
Fictious ipv6 zone is
Fictious zone file name


; IPv6 reverse zone

; The prefix used in this example is 3ffe:b80:1234::/48

; Replace 1234 with your actual prefix in all places.



@ IN SOA (

2001110500 ; serial

3H ; refresh

15M ; retry

1W ; expiry

1D ) ; mininum





; network part /64 | Host part 64 bits |


; 3ffe:0b80:1234:0001:0000:0000:0000:0001


; -------------------------------,

; Your Network| Your prefix (48 bits) |

; -------|-------|-------|-------|



; Hosts of your network


; 64 bit host address part.

;------|-------|-------|------- in ptr


; End of zone

3. Add the new zone to your named.conf file

Here's an example for bind 8 :

zone "" {

type master;

file "";

allow-transfer {none;};


Restart bind. Check for errors in the log file.

3. Add the dns_server option to your tspc.conf file

The syntax is :


No spaces are allowed with this option.

In our example it should look like :

4. Run tspc

This will send the name server name and request reverse DNS delegation.

Make sure that your name server is defined in the DNS name space or the tsp client will complain.

5. Test the delegation

Delegation configuration may take several minutes.

Try to query for NS :

dig NS

6. Test your dns server

Try to query your prefix :


dig SOA

Reverse DNS should now be delegated to your server.