Ubuntu / Mint Linux Users: disable Network Manager connectivity checks
From Free Knowledge Base- The DUCK Project: information for everyone
- You can disable connectivity checking inside the menu: Preferences -> System settings -> Privacy -> Connectivity.
In the System Settings dialog under "Internet connectivity" is an ON/OFF toggle with the description: "Check that network connections can reach the Internet. This makes it possible to detect captive portals, but also generates periodic network traffic."
You DO NOT NEED nor benefit from connectivity checks if you are on your home computer connected to your own LAN or on an office computer connected to an office LAN, especially if connected via an Ethernet cable as opposed to wireless. It is best to disable it unless you are using a laptop and plan on visiting an Internet Cafe (or public wifi)!