For those of you who watch their incoming/outgoing internet connections closely, you may have noticed the domain 1e100.net pop up periodically for seemingly no reason, and in some instances you may have a persistent connection to it – even as soon as you start your computer.
What is 1e100.net? It’s Google. A WHOIS lookup for that domain reveals it’s owned by them.
Why would Google use an "weird" domain name like 1e100.net? It’s symbolic of a googol (10×10^100) which is where Google gets its name from.
Being that most people aren’t aware of this, the first reaction upon seeing this in a network management program, such as a software-based firewall, is to block it because they don’t know what it is. It further freaks people out if it shows up as a persistent connection that they can’t get rid of.
The 1e100.net domain will never show up by itself. It will always be a subdomain such as server-name.1e100.net.
Instances where you will see the 1e100.net connection
(By "see" I mean literally seeing this from a network utility that can closely monitor all network requests.)
Any web page that has embedded YouTube video
For YouTube itself (a Google property) or any other web site that has a YouTube video embedded in it, 1e100.net will show up even if the video isn’t loaded. When the Flash player first launches it makes a request to YouTube for the video thumbnail image and therefore requests 1e100.net for that data.
Firefox "safe browsing"
This feature by default is enabled and uses a Google server to check web sites you load to see if they’re in the "bad" list.
This is located from Tools / Options / Security:
The two checkboxes "Block reported attack sites" and "Block reported web forgeries" enable Firefox to check every single web site you load against the "bad" list Google has.
Uncheck these two boxes if you don’t want where you surf to be checked against the Google list.
If you want to see the actual configuration data for this, load the address about:config in Firefox, then search for safebrowsing, like this:
You don’t have to necessarily do anything here, but if you wanted to know "How much Google is in my Firefox?", there’s your answer.
Google Earth / Google Updater
Both Earth and Updater (which Earth installs by default) will make connections to 1e100.net to check for updates.
You can instruct Updater not to do that if so desired.
As far as I’m aware, the three above instances are where you will see 1e100.net appear. Now that you’re aware what it is and its purpose, you now know it’s not spyware or malware. It’s Google. Using a weird domain because.. um.. well.. it’s a really long (but not really) story and we’ll leave it at that.