Upon starting Firefox and web browsing, when I perform a netstat -tuape, I find a network connection opened and shut down which points to a server *.clients.your-server.de.
Upon further investigation with
sudo netstat -tuape <enter>
it was found that this shows up each time I start up Firefox and enter a URL to visit. Could not figure out what it was. Finally, came across this post, http://www.emaildiscussions.com/showthread.php?t=64875, which stated that it was the Show IP addon in firefox that was the root cause of this connection.
Show IP is a Firefox addon that displays the IP address of any web site you visit in the Firefox web browser. It has it’s uses if you want to know that information.
To eliminate this unwanted connection, you can remove the Show IP addon, or you can click on Tools -> Add-ons -> Extensions and look for Show IP in the list.
Next, click on Preferences and un-check the 3 check boxes under Request remote information.
You can also select the option “Disable Remote Data” in the add-on bar in Firefox at the bottom of the screen, where you see the IP address of the web page you visited.
Restart Firefox and check if it fixed the issue.