Connection Loop Problem

When working with Proxifier, users may encounter a situation in which a connection or DNS name resolution request falls into an infinite loop. Such situations can seriously threaten stability. In the worst case, network access can be completely blocked.
This can happen when a local proxying program is running on the system (e.g., tunneling or antivirus software).

Consider the following scenario:

1. The application initiates a connection or a DNS request.
2. Proxifier captures it and redirects to the local proxy server, or the proxying program intercepts the connection automatically.
3. The proxying program forwards the connection to the internet.
4. Proxifier captures this connection and redirects it again.
5. Step 3 is repeated.

Steps 3 and 4 will repeat forever until the system can handle new connections.

Proper Proxification Rules can prevent this problem. Basically, Proxifier should be configured to bypass the connections made by a local proxy, and Handle Direct Connections options should be disabled. In the case of a DNS name resolution loop, you may also need to disable name resolution over proxy.

Proxifier has a built-in mechanism to detect and prevent such situations. You can enable/disable this feature with the following options in Proxifier’s menu:

• Profile -> Advanced -> Infinite Connection Loop Detection
• Profile -> Advanced -> Infinite Name Resolution Loop Detection

When the first option is enabled, Proxifier uses adaptive logic to continuously monitor connections on the system. If an infinite connection loop is detected, the following error message outputs to the log, the window below appears, and all new connections are automatically blocked until the user responds.

Infinite loop connection detected. All new connections will be blocked automatically till the user action.

Proxifier will suggest one or two actions to prevent future connection loops, allowing you to either apply the actions automatically or disable the loop detection logic. If you click the Cancel button or close the window, nothing will be changed, and the loop detection logic remains active. You are advised to take action manually to address the problem; otherwise, the logic will likely be triggered again soon.

In the case of a DNS name resolution loop, Proxifier outputs the following error message in the log and disables name resolution over proxy.

Name resolution over proxy has been automatically disabled to prevent infinite loop.

It is recommended that users disable the Infinite Connection Loop Detection and Infinite Name Resolution Loop Detection features only in response to false positive detections.