Why do we ping the IP 4.2.2.2 to test connectivity?

For as long as I can remember, I've always used the IP 4.2.2.2 when testing network connectivity using ping. What is significant about this IP, and when did this practice start?

I ping it because it has always been up, and is easy to remember when DNS isn't working. But you might want to read this for more information: http://www.tummy.com/Community/Articles/famous-dns-server/.

Hey everybody... it's me, Dan. I'm the guy who made this claim, and I'm here to talk more about it. Here's the long, drawn-out version of what happened.

I was managing a NOC for a fixed-data wireless company in Florida at the time- fuzion (gofuzion.com - I could write a book about that place). I had a few guys working with me that were relatively new to the networking world. Heck, at that time, so was I, only having a few years of skin in the game.

Because of the novice-level skills brought to bear, I had guys who couldn't pull up a website on their own workstation and would freak out that the 'Internet was down'. Honestly, it was pretty pathetic. One kneejerk reaction everyone had was to ping yahoo.com. That's nice, but involves DNS resolution, so it's prone to failure. They, of course, couldn't remember the IP address to Yahoo, and Google wasn't up (to any real degree) at that point, so what was a simple IP address that everyone could remember that would be up and work reliably and consistently? Remember, this is many years ago, when carrier stability was a sales point, not a forgone conclusion.

I had, at that time, recently put together our WUG (version 3 I think, yay!) map together and wanted some outside hosts for checking. I wanted a pure-ip address that was easy to recognize as well. I putzed around and pinged simple addresses... 1.1.1.1, 2.2.2.2, and so on. I thought about a conversation I had with my boss earlier in the day (a truly gifted man by the name of Robert Campbell), who related back the resiliency of the PSTN. It hit me... telephone service had 411 for information. 4.1.1.1 ... just one more digit and boom goes the dynamite... and it PINGS!. I put it in my WUG map and forgot about it for a week or two.

I go back to review my map and this host has never gone down. I was too lazy previously to see who it belonged to, but now my curiosity was piqued. How stupid did I feel? It was a DNS server for GTE. Of course it was bound to be up most of the time. Back on the floor of the NOC, guys were still being dumb (this, for some, never changed. I'm sure all here can relate. We had a term for them pulled from the Denver office... "tits on a bull". But I digress.) They'd freak out when they or a client would have connectivity problems... and from there I told them, "Ping 4.1.1.1 . It will always work if your connection to the general Internet works. It's like 411 for the Internet." I know, super-cheesy. But I learned that super-cheese worked in tense situations, not just with nachos.

It worked. Guys stopped trying to ping DNS names or remembering their home cable/dsl address that would likely change anyway. They could just remember this simple address.

One day, I suppose they turned off ICMP- it stopped working. Guys in the NOC weren't crying, but they definitely had their panties in a twist. "4.2.2.2" was given in frustration by moi, which also coincidentally was the secondary to 4.1.1.1 (I think, could be wrong), and was responding to ICMP. It stuck. It spread. That's how it goes sometimes.

On the phone I heard these guys telling clients to ping 4.2.2.2 to test connectivity. I heard them on the phone with vendors testing with the address. What made me smile one day a couple years later was a frantic front-line DSL phone tech walking me through my home connectivity outage. "Ping 4.2.2.2" she quipped. Did I feel a little warm inside? You betcha.

So that's it. Did I invent it? For me in my little world, yes. Could someone else have already (or somewhat simultaneously) done it, like the radio or flight or any other actually important thing that has some actual impact in our lives? I hope this puts an end to the rumors. (reposted on mywebsite)