Troubleshooting network problems

Most often, connection problems occur because a firewall, proxy server, corporate network, or other network is configured in a way that blocks Che.

This section describes how to prevent or resolve issues related to corporate network policies. The network administrator may be required to enable ports or the WebSockets protocol, which Che requires for proper functionality.

Common scenarios:

  • Open additional ports for a specific web site.

  • Enable WebSockets on the proxy server.

Enabling the WebSocket protocol

Enabling the WebSocket protocol is critical for the proper functionality of Che IDE.

While the WebSocket protocol itself is unaware of proxy servers and firewalls, HTTP servers can share their default HTTP and HTTPS ports with a WebSocket server.

  • HTTP: port 80

  • HTTPS: port 433

Some proxy servers operate with WebSockets by default, but others prevent WebSockets from working correctly, which causes the connection to fail.

In some cases, the proxy server requires the additional configuration, and the specific proxy servers need an upgrade, which allows WebSockets support.

Troubleshooting WebSocket Secure connections

Secure WebSocket connections improve confidentiality and also reliability because they reduce the risk of interference by bad proxies. Che operates under WebSocket Secure connections by default and usually no action is required. Some customer’s security policy blocks some aspects of the WebSocket protocol that causes problems with proper Che functionality. Those problems are however out of scope for Che support and have to be solved by a network administrator.

To troubleshoot a failing WebSocket Secure (WSS) connection, use the instructions in this section.

  • Using a supported web browser:

    • Chrome

    • Firefox

    Using an unsupported web browser causes a connection interruption, followed by a warning message.
  1. Check browser support:

    1. Check that the WebSocket protocol is enabled using a realtime web test in one of the supported browsers.

      If the problem is not resolved, follow with the next step.

  2. Check proxy servers and firewalls settings:

    1. Ask the system administrator to check if there is a proxy server or firewall that blocks WebSocket Secure (WSS) connections on port 443.

      Possible required actions:

      • Add an exception to the firewall.

      • Have the proxy intercept WebSocket connection.


Check that the WebSocket protocol is enabled using a realtime web test in one of the supported browsers.