|ddns.nu® frequently asked questions|
FAQ - frequently asked questions
What is DDNS?
Dynamic DNS, in a nutshell; a way to keep a DNS hostname pointing at a dynamic IP address
How much does it cost?
Nothing, at least for the provided 'core' domains and 'shared' domains, but shared domains have some pitfalls, read on.
How does it work?
A lengthy answer; our servers keep a record of your IP in an object we call an 'IP-Handle', we also know what hostnames you have chosen, we call them 'DDNS-Records', all of this information is exported by our DNS servers to the global DNS. The nice part comes when your IP changes, all you have to do is change your IP-Handle to match the change and all of your DDNS-Records will follow.
How do I use the client?
Take a look at this short excerpt from an email I sent answering this question.
I have to register to use ddns.nu, why?
House keeping. In particular for your own security we need an identity which 'owns' all your DDNS-Records and IP-Handles (and perhaps Domains). We ask only for you full name and email address, you can pick your own username and password. Optionally you can supply your telephone number for rapid contact, but it is not required. Your email address is required for administrative contact, especially if you use shared domains.
Do I own my hostname?
No, not in the sense of a domain registration. The ddns.nu site owners are the registrants of the 'core' domains, and have full naming control over them, our decision is final, we reserve the right to delete records, etc. Don't let this concern you too much, unless you delete your usage of a record no one else can steal it from you (except us :), and unless we receive a complaint we won't censor records.
Where do I start?
What is IN A and IN MX?
An IN A record is a hostname to IP mapping. This is the most common form of DNS record, and the type you want for making yourhostname.cable.nu point to your IP.
What is this Pri thing on MX records?
This is the priority or prescedence of an MX record. If more than one MX record is present for a domain, they are searched in order of increasing value by this number. The first server that answers is given the email. Unless you have multiple mail servers, you don't need to worry about this.
What does the expiry value mean?
This is the time-to-live given out by the DNS server for the record in question. Basically it is how long a remote DNS server may cache the result of a lookup on this record, or how long incorrect information may be visible after a change.
commercial service ('private' and 'shared' domains)
Can I use my own domain?
Yes. There are two options.
How much does it cost?
Private Hosting: $10 australian per month per domain
Where do I delegate to?
We'll supply that information when you register for the commercial service (either 'shared' or 'private'). The basic commercial registration process is:
Why isn't shared hosting free? After all we are loaning our namespace to you.
The fee, which is very small, just over $2/month, covers our infrastructure costs. It is your rent for the bandwidth, time, and effort that goes into providing the hosting. This discount (20% of the full private hosting fee) is our thanks for helping make ddns.nu so sucessful. We prefer to think of it as you loaning the ddns.nu community your namespace, rather than you loaning it to ddns.nu.
Will you licence it to me?
Why would we need to? The shared domain lets you be your own DDNS provider, albeit under our branding. We are open to enquiries, but ddns.nu is not about profit, if we make enough to pay for our DNS request traffic we are having a good month.
Can I write my own client?
Yes, and we encourage it. The protocol spec is open, and there are two reference implementations available, one C and one Java. If you do make one, we'd love to know about it, so we can tell all ddns.nu users about it. We don't mind if you make it commercial, or build into into a commercial product, just remember to mention us in there somewhere :) (not that the client is much good without a server and the rest of ddns.nu)
What about RFC compliant DNS update messages?
Currently there is no standard for secure updates. Several recent DHCP implementations support 'true' DDNS, but not of sufficient security to be used outside of LANs. If this comes along, there'll be a ddns v4 released. At present we just ignore the reject messages scrolling by in the logs.