DHIS: Making IPv6 Address Updates

IPv6 Updates

Just like with IPv4, DHIS accepts updates of IPv6 addresses; the two are independent which means that you can have both an IPv4 and an IPv6 address pointing to your same unique hostname under dhis.org. Here is how it works:

You need to use Web Updates; old release 5, 4 or 3 DHIS clients do not support IPv6.

Instead of using is.dhis.org, use is6.dhis.org as the hostname. This hostname only has a v6 address and as such can only be reached by IPv6. So use something like https://is6.dhis.org./update/...

When you create a DHIS host in the control panel it will be given an IPv4 address but will *not* have an AAAA (IPv6) record until you update it for the first time with IPv6.

Just like the IPv4 DHIS hosts get the 192.168.255.0 IP address when offline, IPv6 DHIS hosts get a random unique local IPv6 address as described in RFC4193.

The update method is exactly the same as the one used in IPv4 web updates; as long as you make your HTTP request using IPv6 the update server will be able to detect your remote IP address and will use it to create the AAAA record; if you specify the IPAddr="v6addr" parameter, then "v6addr" takes precedence and is used instead. Your host has a configurable update timeout, and after this period if we don't hear from you your host is marked offline.

Please See: Configuration Guides : DHIS on a UNIX server with wget and cron for examples of how to update IPv6 addresses using wget.

6to4 Addresses

6to4 addresses are IPv6 addreses used in 6to4 tunnening to encapsulate IPv6 over IPv4. They are somehow special because they encapsulate the v4 address in the v6 address and allow tunnels to be configured automatically. 6to4 addresses always start with the 2002::/16 anycast prefix.

IPv6 6to4 Anycast Address
16 bits	32 bits	80 bits
2002	IPv4-Embedded Address	/48 End-User prefix

By default the DHIS server recognises 6to4 addresses and when you submit an update from one of these sources, it constructs your IPv4 address (looks at the embedded address) and also updates your IPv4 DNS A record. This means that you will update 2 addresses (1xIPv4 and 1xIPv6) with a single update request.

In order to disable this behaviour and perform an IPv6 only update using a 6to4 address, you can use the Update6to4V4=No HTTP form variable to signal it to the server.

The following URL will update your 6to4 address without updating its corrresponding IPv4 address:

http://HostID:HostPassword@is6.dhis.org/?Update6to4V4=No

Next Topic: Live Web Updates