Sunday, April 29, 2012

What's My DNS

I use a very simple, yet helpful, DNS tool:

Many times, I'll make a DNS change to one of my servers or hostnames and I'll wonder how well it's propagated across the entire Internet.

In "the old days," a host name generally pointed to a single IP address no matter where in the world you were when you tried to access that domain name.

But, in today's world of redundant cloud storage, you will have a hard time locating the exact server where your web resources are located. It's much like trying to locate an electron's position and momentum in an electron cloud. I host on Amazon's S3, which has about a dozen different IP addresses.

While Amazon S3 guarantees at least triple redundancy, it might, actually, be better than that.

Always keep in mind when playing around with DNS updates that it's best to set the TTLs to something very short for the new DNS entries and, doubly so for negative caching TTLs. I generally keep these specific TTLs to less than 60 seconds with a generic * hostname also set to a very short time period.


Sandra said...

As an alternative to, you can rely on
for more detailed propagation results, with over 100+ public servers available to check the live propagation results.

Sandra said...

With time more tools are also introduced to check the live DNS propagation results. One of them is Personally, I used that tool, because of its more detailed propagation lookup report, as compared to any other similar online tool. With over 100 public servers available to check the live DNS propagation results, with the facility to even add your own custom DNS server.