Tuesday, October 19, 2010

DNS Propagation

We all tell clients that DNS changes take 24-48 hours to propagate, but we very rarely get to see any evidence of this. Well, now I have a nice chart showing just this.

A website that I am, ahem, involved with, went offline for a period of time earlier this week on account of a ‘miscommunication’ with the company hosting the DNS name servers. As a result, they removed the DNS record from their servers, and the domain simply disappeared from the internet. The solution was pretty simple – update the name servers to the current hosting provider (the ever reliable Rackspace, who I have no hesitation in plugging – their service desk is fantastic). Then all I had to do was sit back and wait.

Fortunately, at the same time the site was being monitored by the equally reliable Pingdom, who monitor the site from 25 locations in 10 countries across Europe and North America (not representative of the world, I know, but enough to make this interesting).

This meant that I could watch the propagation of the DNS change as it was picked up by their servers. Again, this is not a scientific survey, but interesting nonetheless.

dns_propagation

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