Скачать или смотреть Solving the MongoDB Connection Error in Node.js on localhost

Discover how to resolve your `MongoDB` connection issues in `Node.js` and access your databases seamlessly by understanding your localhost setup.
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This video is based on the question https://stackoverflow.com/q/69921850/ asked by the user 'Candleout' ( https://stackoverflow.com/u/5540785/ ) and on the answer https://stackoverflow.com/a/69922050/ provided by the user 'Christian Fritz' ( https://stackoverflow.com/u/1087119/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Can't Access MongoDB on Localhost in Node.js? Here's How to Fix It!

If you're a developer trying to set up a Node.js application with MongoDB, you might encounter issues when trying to connect to the database on localhost. Don’t worry! You’re not alone in this dilemma, and in this guide, we’ll tackle the problem at hand and provide clear steps to resolve it.

The Problem: Connection Issues

In this particular case, a user has successfully installed MongoDB and can interact with it in the terminal as well as through a GUI client like Compass. However, they can’t establish a connection using Mongoose in their Node.js application when attempting to connect with the standard localhost URI. This results in the following error message:

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This error indicates that the connection is being refused on the IPv6 address (::1) instead of the intended IPv4 address (127.0.0.1). This commonly occurs when there’s a mismatch between how localhost resolves and how the MongoDB server is set up.

Understanding localhost and IP Addresses

By default, MongoDB binds to the IPv4 address 127.0.0.1. When you try to connect to localhost, it might resolve to the IPv6 loopback address, which is represented as ::1. Consequently, your connection attempts to this address will fail since the MongoDB server isn’t listening on it.

Steps to Solve the Issue

There are several ways to remedy this situation. Let’s break down the options you can explore:

1. Use the IPv4 Address Directly

The simplest solution is to modify your connection string to explicitly use the IPv4 address:

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This should allow your application to connect to the MongoDB instance without any issues.

2. Modify MongoDB Configuration

If you prefer to use localhost, you can edit the MongoDB configuration file to bind to the IPv6 address. The mongod.conf file is typically located where MongoDB is installed. Look for the bindIp option and change it to include ::1:

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After saving the configuration changes, restart your MongoDB server to apply the new settings.

3. Change localhost Resolution

Another option is to modify how localhost resolves on your machine. On Linux and macOS, you would edit the /etc/hosts file to ensure it points to 127.0.0.1. On Windows, you can find it under:

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Make sure it includes an entry like:

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And remove entries that point localhost to ::1. Once that’s done, restart your network connection or flush your DNS cache.

Conclusion

In conclusion, understanding how localhost resolves to different IP addresses and adjusting your configurations can solve your issues with MongoDB connectivity in Node.js. Whether by directly using 127.0.0.1, changing the MongoDB configuration, or adjusting localhost resolution, you have multiple pathways to a seamless connection. Now, go ahead and implement these solutions to get your application up and running with MongoDB!