Thursday, March 6, 2014

Cyberspace can break


There was a problem on February 28th when a few of our clients couldn’t reach our website. Naturally, they thought we were having a problem.  However, in fact, the problem was neither with our website servers or their Internet connection. We knew this because the vast majority of our clients could reach our website and those who couldn’t were able to successfully access other websites. So what went wrong?

When someone enters www.DomainNameSanity.com (or any other domain name) into their Internet browser, the first step is to know where on the planet the website server sits. That’s done by having your Internet Service Provider (“ISP”) process a “DNS name resolution”. That means that the ISP looks-up which “domain name server” is storing the location of the website server you are trying to reach and then, requests that location. That location of any device connected to the Internet is called an “IP Address”. The letters IP stand for Internet Protocol. Once your computer knows the IP Address, it sends a request to that website server to deliver the content of a specific page to them.

Web pages contain a lot of data and it’s not possible to send that data in a single message from the website server to you. What happens is that that website server gets the request and sends the data in small “packets” of information. Once all of those packets arrive at your computer, they are combined by your web browser to form the website page.

Since there’s no direct connection from your home to any website server and back, those packets of data are routed over Internet by passing the packets of data through a number of different connections owned by a number of different companies. In fact, the packets of data for any single webpage, probably take different paths to get to you. Once the last package of data arrives, it’s pulled back together and shown to you. It’s very common for different segments over which the packets travel to fail. When that happens, the packets of data will be automatically rerouted along a different path so they arrive safely. However, on occasion, there’s a major failure in the Internet and an alternative path isn’t available. In that case, you cannot reach the website despite you having a good Internet connection and the web server working properly. Failures of this nature typically last just a few minutes. However, we have seen them last up to 6 hours (and perhaps they have lasted longer without our noticing). These failures can happen during extreme weather conditions. When there is a failure of that type, while you cannot reach the website, others who use completely different paths to get to the website server have no problem at all.

You can actually see one of the paths between your computer and a website server. I’ll use the path to Facebook as an example. Facebook has an IP address of 173.252.110.27. On a Windows computer, you need a “command” prompt. That’s typically done by typing “command” into the Windows search box and selecting that program. On Apple Mac OS, it is available by opening “Network Utilities” then selecting “Traceroute” tab, as well as by typing the "traceroute" command in the terminal.

You then type:  tracert 173.252.110.27. Here’s the result on my Windows computer from my office to Facebook:



You’ll note above that the tracert command is going to limit itself to 30 “hops” or handoffs of data. This gives you some indication that many hops are normal.  This connection starts at 192.168.0.1 which is the IP address assigned by my ISP in the router in my office to my computer. The next step is through “rr.com” because that’s the system that my ISP, Time Warner, uses. It’s passed through other connections until it gets to a main Internet connection at “LAX1.gblx.net”. It’s then passed along until it gets to Facebook’s control where they direct it to a specific location within their system.

This entire process to lookup Facebook’s IP address and then route the information takes perhaps a second; even if you’re on the other side of the world from Facebook due to data traveling close to the speed of light across fiber optics.

So, when you cannot connect to an Internet site, it’s not necessarily that Internet site that’s having the problem or even your computer. There can just be a breakdown in “cyberspace”.

No comments:

Post a Comment