Networking in IntelliJ IDEA
IntelliJ IDEA requires Internet connection for a wide variety of tasks. For example:
Checking for IntelliJ IDEA updates
Code inspections that can verify external resources
Communication with the version control servers, task servers
Anonymous usage statistics
Resolving Maven dependencies and updating plugins
Using the IDEtalk plugin
Besides that, IntelliJ IDEA provides IPC for commands (for example, open files), and the built-in Web server.
Some of the communication requirements are configurable:
To turn off checking for updates, open the Settings | Updates page, and clear the Check for updates in channel checkbox.
To turn off IDEtalk plugin, open the page Settings | Plugins, and make sure that the checkbox to the left of the plugin name is cleared.
To use only those Maven resources that are available locally, open the page Settings| Maven, and select the checkbox Work offline
To disable code inspection that highlights dead links, open the Settings | Inspections page, and clear the checkbox to the left of the HTML inspection Non-existent web resources.
You can control the frequency of sending usage statistics, or even completely disable this function in the page Settings | Usage statistics.