Monday, April 11, 2011

Updating DynDNS via commandline in ubuntu

Updating Ubuntu via command line for DynDNS might be something you need to do as well, here is an easy way to get that done.

Running a Linode I decided it would just be easier to use Dynamic DNS for the name as I am a firm believer in using DNS for everything over remembering IP Addresses. The problem with DynDNS is that after 30 days of no updates it will expire any DNS entry you have submitted if it isn’t updated, for this reason you need to have some sort of automated update utility in those situations to just keep the lights on.

Install the package via apt

sudo apt-get install ddclient

The gui then runs in command line with pretty straightforward questions that you can answer easily (such as your user and password), you can even let it detect your dns entries available from that account.
once that is done it is best to configure the system to actually auto update do this by editing the conf file

sudo nano /etc/ddclient.conf

add the following line


that number is the number of seconds in 12 days, you can make that whatever you want but I have a static IP so all i want it to do is update faster than the minimum expiry window which is a month, this way it tries twice in a month in case the first one tires out for any reason.

Hint: if you are too lazy to figure out “12 days in seconds” like me, just google exactly that phrase and it will convert it for you!

Why Bother with DNS updates at all if you have a static IP?

I find this is more than ever a good habit with the inevitable IPV6 impending doom, you might find it easy to remember your current 32-Bit address such as but how will you be when that IP changes to 0000:0000:0000:0000:0000:0000:0a01:0164, seems simple now since you are only using the first 32-Bits for them but once we start using the rest of that 128-Bits, everything will change. There will be no asking someone to ping fe80:0:0:0:202:b3ff:fe1e:8329 will there? (or at least I hope not).

If you need more guidance because things aren’t working how they should then there is a great article on the Ubuntu site.

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