Fixing Dify's [Errno 111] Connection Refused Errors

Experiencing a [Errno 111] Connection refused error can be one of the most frustrating hurdles when you're developing or deploying applications, especially within sophisticated platforms like Dify and LangGenius. This error message, while seemingly simple, points to a fundamental communication breakdown: your application tried to connect to another service, but the server on the other end flat out refused the connection. It’s like knocking on a door only to find no one answering, or worse, someone actively blocking your entry. In the context of modern application development, where microservices, external APIs, and internal nodes frequently interact, resolving this issue swiftly is paramount for maintaining smooth operation and data flow. This isn't just a minor glitch; it can halt critical processes, preventing your Dify agent from fetching essential data, integrating with vital systems, or executing its intended functions. For anyone working with Dify to build intelligent applications, encountering this error, particularly when trying to access internal resources like http://192.168.56.66:5023/api/get_customer_data/C00001, signals a need for immediate and systematic troubleshooting. We'll dive deep into what this error means, common causes, and a methodical approach to diagnosing and resolving it, specifically focusing on how your network configuration, firewalls, and proxy settings within a Dify environment can play a crucial role.

Understanding [Errno 111] Connection refused

When your Dify instance, or any application for that matter, throws a [Errno 111] Connection refused error, it means a client (in this case, Dify's ssrf_proxy.py module) attempted to establish a TCP/IP connection to a specific server at a given IP address and port, but the server explicitly denied the connection request. This isn't a timeout, where the server is slow to respond; it's an active refusal. There are several primary reasons why this might happen, and understanding each is key to effective troubleshooting. First and foremost, the most common culprit is often that the target service isn't running or isn't listening on the specified IP address and port. Imagine calling a phone number, but the phone isn't plugged in, or it's turned off entirely. The system receives the call attempt but has nothing to route it to. Similarly, if your get_customer_data service on 192.168.56.66 isn't active or has crashed, Dify's request will be immediately refused. Secondly, the IP address or port might be incorrect. A simple typo in the configuration, using 5023 instead of 5032, or pointing to 192.168.56.66 when the service is actually on 192.168.56.67, will lead to this error. The client attempts to connect to a non-existent endpoint for that service. Thirdly, firewall rules, on either the client (Dify's host) or the server (192.168.56.66), could be blocking the connection. A firewall acts as a digital bouncer, deciding which connections are allowed in or out. If a rule exists that explicitly denies traffic on port 5023 from Dify's host, the connection will be refused. Fourthly, network configuration issues can contribute. This includes routing problems, incorrect subnet masks, or even complex VPN setups that prevent direct communication between the Dify host and the target service. While less common than the other issues, an improperly configured network can create invisible barriers. Finally, and crucially for Dify users, proxy configurations can sometimes interfere, even when they shouldn't. Although you might have specified certain IPs to bypass the proxy, a misconfiguration or a specific library's behavior could still attempt to route traffic through the proxy, which then can't reach the internal IP directly. In the context of Dify, which often operates in complex environments, any of these factors can prevent its nodes from interacting with your valuable data sources, making [Errno 111] a critical error to resolve.

Diagnosing the Problem in Your Dify Setup

When [Errno 111] Connection refused pops up in your Dify logs, it's time to put on your detective hat. Our goal is to systematically eliminate potential causes. First and foremost, we need to address the most common and often overlooked issue: Is the Target Service Running? This is your very first step. You mentioned Dify is trying to reach http://192.168.56.66:5023/api/get_customer_data/C00001. You need to log in (SSH) to the server at 192.168.56.66 and confirm that a service is not only running but actively listening on port 5023. You can use commands like sudo netstat -tulnp | grep 5023 or sudo ss -tulnp | grep 5023. The output should show a process listening on 0.0.0.0:5023 or specifically 192.168.56.66:5023. If it's listening only on 127.0.0.1:5023 (localhost), then external connections from Dify will be refused, as the service is not exposed to the network interface Dify is trying to connect to. If no process is listed, the service isn't running at all, and that's your immediate fix: start the service. Once you confirm the service is alive and listening correctly, the next step is Network Reachability. From the Dify host, can you reach 192.168.56.66? A simple ping 192.168.56.66 will tell you if basic network connectivity exists. More importantly, you need to check if the specific port 5023 is reachable. Use telnet 192.168.56.66 5023 or nc -vz 192.168.56.66 5023 (netcat). If telnet immediately says