3x-ui Panel Bug Report WARP Inaccessibility And SSH Failure

Hey guys! Today, we're diving deep into a fascinating bug report concerning the 3x-ui panel and its interaction with WARP. This issue, reported by MHSanaei, highlights a peculiar problem where enabling WARP can lead to the panel becoming inaccessible and SSH connections failing. Let's break down the problem, explore the steps to reproduce it, and discuss potential solutions. This article aims to provide a comprehensive understanding of the issue, making it easier for both users and developers to grasp and address. We'll cover everything from the initial bug description to the workaround, ensuring a thorough exploration of the topic.

Describe the Bug

The core of the issue lies in the WARP outbound rule within the 3x-ui panel configurations. When this rule is active, the panel becomes inaccessible, and SSH connections to the server fail. However, this only occurs when attempting to connect through the same server. This specific behavior suggests a routing conflict or a loopback issue when WARP is engaged. The user, MHSanaei, discovered that the problem arises specifically when the traffic is routed back through the server itself, which is a critical detail in understanding the nature of the bug. Let's delve into the specifics to understand the root cause and how to address it effectively. This issue is particularly crucial because it affects the fundamental accessibility of the server and its management interface, which can lead to significant operational disruptions if not properly addressed.

The workaround implemented by MHSanaei involves modifying the routing rules to explicitly bypass WARP for the panel domain and the server's IP address. By routing these through a separate IPv4 outbound, the issue is resolved. This workaround provides a temporary solution but also highlights the importance of proper routing configuration in mitigating such problems. The specific configuration added includes two routing rules: one for the panel domain (my.domain.com) and another for the server's IP address (X.X.X.X). Both are directed through an IPv4 outbound, effectively bypassing the WARP rule that was causing the conflict. This manual intervention underscores the need for a more robust and automated solution within the 3x-ui panel to handle WARP configurations seamlessly without disrupting essential services like panel access and SSH connectivity. It also points to the potential for more user-friendly interfaces to manage these routing rules, making it easier for administrators to maintain their servers.

How to Repeat the Problem?

To reproduce this bug, follow these precise steps, guys:

1. Enable WARP on the 3x-ui panel without adding any geoip/geosite blocking rules. This initial step sets the stage for the conflict by activating the WARP outbound rule, which will become the focal point of the issue. Ensuring no additional blocking rules are in place helps isolate the problem to the core interaction between WARP and the panel's accessibility. This clean setup allows for a more accurate replication of the bug and ensures that other configurations do not interfere with the outcome.
2. Disable UFW (Uncomplicated Firewall). Disabling the firewall is crucial because it eliminates any potential interference from firewall rules that might mask or alter the behavior of the bug. UFW is a common firewall management tool, and deactivating it ensures that the traffic flow is solely governed by the routing configurations within the 3x-ui panel and the WARP settings. This step is vital for accurately simulating the conditions under which the bug occurs and preventing any false negatives during testing.
3. Connect to the internet using a VPN running on the same server (e.g., VLESS or VMess). This is a key step in triggering the bug. By using a VPN hosted on the same server, you create a scenario where traffic is routed through the server itself, which then interacts with the WARP outbound rule. VPNs like VLESS or VMess are commonly used in conjunction with 3x-ui for secure connections, making this a realistic and relevant test case. The loopback nature of the traffic flow when using a local VPN is what exposes the conflict with WARP.
4. Attempt to access the panel or connect to the server via SSH using this VPN. This final step reveals the bug. When the panel becomes inaccessible or SSH connections fail, it confirms the presence of the issue. The inability to reach the panel or the server through SSH indicates that the WARP outbound rule is interfering with the routing of traffic, specifically when it is initiated from within the same server. This outcome is the definitive sign that the bug has been successfully reproduced, allowing for further investigation and resolution.

Expected vs. Received Action

The expected action is that the panel and SSH access should remain functional even when connecting via a VPN running on the same server. The system should handle the routing without causing interruptions to these essential services. Smooth operation under these conditions is critical for maintaining server accessibility and manageability. Any deviation from this expected behavior indicates a problem in the configuration or the system's handling of network traffic.

However, the received action paints a different picture. When the WARP outbound rule is enabled, the panel becomes inaccessible, and SSH connections fail specifically when accessed through a VPN running on the same server. This disruption highlights a clear discrepancy between the intended functionality and the actual outcome. The inability to access the panel and establish SSH connections under these circumstances significantly impacts server administration and maintenance, making it essential to address the root cause of this issue. The contrast between the expected and received actions underscores the severity of the bug and the need for a reliable solution.

Software Versions

• 3x-ui Version: 2.6.2
• Xray-core Version: 25.7.26

These version numbers are crucial for identifying the specific environment in which the bug was observed. Knowing the versions of both the 3x-ui panel and the underlying Xray-core helps developers pinpoint the source of the issue and determine if it is version-specific. This information is invaluable for debugging and testing fixes, as it ensures that the solution is tailored to the exact software configuration where the problem arises. Providing these details upfront streamlines the troubleshooting process and facilitates a more effective resolution.

Checklist

• [x] This bug report is written entirely in English.
• [x] This bug report is new, and no one has reported it before me.

These checklist items confirm the validity and originality of the bug report. Ensuring that the report is in English makes it accessible to a broader audience of developers and users. Verifying that the bug is new prevents duplicate efforts and ensures that the focus is on addressing previously unacknowledged issues. These steps are important for maintaining the quality and relevance of bug reports, contributing to a more efficient and effective bug-fixing process.

Analysis and Possible Causes

Now, let's dive deeper into what might be causing this issue. The fact that the problem only occurs when connecting through the same server suggests a routing conflict within the server's network stack. WARP, when enabled, likely reroutes traffic in a way that interferes with the loopback connections established by the VPN. This could be due to WARP's routing rules taking precedence over the VPN's, leading to a deadlock or a misdirected connection. A potential cause is that WARP is not correctly handling traffic originating from and destined for the same server, leading to a routing loop or a failure to properly forward the packets. This misconfiguration could stem from how WARP interacts with the server's network interfaces or how it interprets the routing tables. Additionally, the absence of geoip/geosite blocking rules in the WARP configuration indicates that the issue is not related to specific traffic filtering but rather to the fundamental routing behavior of WARP.

Another possible explanation is that the 3x-ui panel's configuration does not adequately account for the simultaneous use of WARP and a local VPN. The panel's routing logic might not correctly identify and handle the traffic originating from the VPN, causing it to be misrouted or dropped. This could be due to a lack of specific rules to handle VPN traffic or an incorrect prioritization of routing rules. The workaround provided by MHSanaei, which involves explicitly bypassing WARP for the panel domain and server IP, supports this theory. By manually defining these routing exceptions, the traffic is correctly directed, bypassing the problematic WARP rule. This suggests that a more comprehensive and automated approach to managing routing rules in the 3x-ui panel is needed, particularly when WARP and VPNs are used in conjunction. A well-designed routing configuration should intelligently handle local and external traffic, ensuring that essential services remain accessible without manual intervention.

Potential Solutions and Recommendations

Based on the analysis, here are some potential solutions and recommendations to address this bug:

1. Enhance Routing Logic in 3x-ui: The 3x-ui panel should be updated to intelligently handle traffic originating from VPNs running on the same server. This could involve adding specific rules to recognize VPN traffic and route it appropriately, ensuring it doesn't conflict with WARP's routing. The routing logic should be designed to prioritize local traffic to avoid misdirection.
2. Improve WARP Integration: The integration of WARP within 3x-ui needs refinement. This includes ensuring that WARP correctly handles loopback connections and does not interfere with local services. Developers should investigate how WARP's routing rules interact with those of the server and the VPN, identifying potential conflicts and implementing solutions to prevent them.
3. Provide User-Friendly Configuration Options: The 3x-ui panel should offer more user-friendly options for configuring routing rules, especially for scenarios involving WARP and VPNs. This could include a simplified interface for defining exceptions or a set of pre-configured rules for common use cases. Clear documentation and guidance should be provided to help users understand how to configure these settings effectively.
4. Implement Automated Conflict Detection: The panel could be equipped with automated conflict detection mechanisms. These mechanisms would identify potential routing conflicts between WARP and other services, such as VPNs, and alert the user or automatically adjust the configurations to resolve the issues. This proactive approach would reduce the likelihood of users encountering accessibility problems.
5. Thorough Testing: Comprehensive testing is crucial to ensure that the fixes and improvements effectively address the bug and do not introduce new issues. This testing should cover various scenarios, including different VPN configurations, network setups, and user environments. Rigorous testing will help validate the robustness of the solutions and ensure a stable and reliable system.

Conclusion

The bug report regarding WARP making the panel inaccessible and SSH connections failing in 3x-ui highlights a significant issue that needs attention. The detailed steps to reproduce the problem, along with the workaround provided by MHSanaei, offer valuable insights into the nature of the bug. By understanding the potential causes and implementing the recommended solutions, developers can enhance the 3x-ui panel and WARP integration, providing a smoother and more reliable experience for users. This exploration emphasizes the importance of careful routing configuration and the need for user-friendly interfaces to manage complex network setups. Keep an eye out for future updates and fixes that address this issue, guys! This collaborative effort between users and developers is essential to maintaining the quality and functionality of the 3x-ui panel.