72 Hours Wacky
December 20th, 2007
Way back in 2003, Verisign made a DNS change that said ‘all fake .com and .net addresses point to THIS address, instead of nothing at all.’ And everyone got pissed off.
I explained to people what DNS was: The software that translates a domain name to the IP address of a server. The IP address is the unique ‘number’ assigned to your server that differentiates it from every other computer. And yes, we will run out of numbers one day. There are ways around this. Like if you have a network behind a home router, you can use the same IP addresses as your neighbor behind HIS router. You’re segregated.
Wikipedia has a nice explantion:
In theory a full host name may have several name segments, (e.g ahost.ofasubnet.ofabiggernet.inadomain.example). In practice, in the experience of the majority of public users of Internet services, full host names will frequently consist of just three segments (ahost.inadomain.example, and most often www.inadomain.example).
For querying purposes, software interprets the name segment by segment, from right to left, using an iterative search procedure. At each step along the way, the program queries a corresponding DNS server to provide a pointer to the next server which it should consult.
A DNS recursor consults three nameservers to resolve the address www.wikipedia.org.
A DNS recursor consults three nameservers to resolve the address www.wikipedia.org.As originally envisaged, the process was as simple as:
1. the local system is pre-configured with the known addresses of the root servers in a file of root hints, which need to be updated periodically by the local administrator from a reliable source to be kept up to date with the changes which occur over time.
2. query one of the root servers to find the server authoritative for the next level down (so in the case of our simple hostname, a root server would be asked for the address of a server with detailed knowledge of the example top level domain).
3. querying this second server for the address of a DNS server with detailed knowledge of the second-level domain (inadomain.example in our example).
4. repeating the previous step to progress down the name, until the final step which would, rather than generating the address of the next DNS server, return the final address sought.
So all this came up again today!
Why? Turns out that our ISP changed our nameservers, and accidentally deleted our info. So they had to re-add it back in, and the prorogation is taking 72ish hours and certain things aren’t working. www.company.com is okay, but remotemail.company.com isn’t, and so on.
Which brings this up. Why does it take 72 hours!?
Propagation means that a change to the nameserver that houses joe.com (or company.com) has to go out and touch all the DNS servers around the world. Disney’s song aside, the world is pretty damn big, and it takes a while for every server in the world to sort out who a person is. Most of the time it happens in a couple hours, but on a busy day it can take the limit of 72. Until the 72 is up, you may see wackiness.
And my office? Ooooh the wacky.
Categories: Smart Things
Hmm.. 72 hours seems way out of line. Typical is 12 hours with a max of 24. Something must be hosed with your ISP, besides having his head up a dark stinky hole.
NO-IP.com updates in 5 minutes.
72 hours is the maximum time it takes, based on how many servers in the world need to be updated. The main issue here was that it was deleted and POPULATED before we noticed it had happened. Frankly I’ve never seen it take more than 10 hours to round-the-world update, and we were fixed by the time I went home.