Persistent Network Connection Failure

johnanderson5
FREE

6 days ago

I am experiencing a persistent network issue with my project and need your assistance. My Node.js/Express backend service is unable to connect to its MySQL database service, and I have exhausted all user-side troubleshooting steps.

The Core Problem:

When my environment variables (like MYSQLHOST) are correctly linked from the database service, my application fails to connect with an Error: connect ETIMEDOUT. This indicates a network block, as the connection attempt times out.

To confirm the variables were being loaded, I temporarily removed them from the service. As expected, the error changed to Error: connect ECONNREFUSED ::1:3306, proving my application was correctly defaulting to localhost. This test confirms the issue is not with my code but with the network path when the correct host variable is present.

Troubleshooting Steps Already Taken:

I have thoroughly debugged this and can confirm the following:

  • Correct Configuration: My app and database are in the same project. My start command is node server.js, and my package.json is configured correctly.

  • Environment Variables: I have confirmed the variable names are correct. The issue persists whether I use the shared MYSQLHOST variable directly or alias it.

  • No Race Condition: I have implemented a connection retry-with-backoff mechanism. The connection fails every time, proving it is not a startup race condition.

  • Health Checks Passing: I have configured my server to start before initiating the database connection, so my /api/health endpoint responds correctly and the service deploys successfully.

  • Service Restarts: I have tried restarting the database service and redeploying my backend multiple times.

  • Variable Re-linking: I have completely unlinked/deleted all database variables from my backend service, redeployed to clear the configuration, and then re-linked them.

The ETIMEDOUT error consistently returns, pointing to a platform-level networking issue between my service containers. Could you please investigate the networking for this project?

Thank you for your help.

$10 Bounty

7 Replies

railway[bot]

6 days ago

Our team is working on getting back to you as soon as possible. In the meantime, we've found the following might help you get unlocked faster:

If you find the answer from one of these, please let us know by solving the thread! Otherwise, we’ll be in touch.

idiegea21
HOBBYTop 10% Contributor

4 days ago

can you confirm that your backend uses Railway’s internal database hostname (not localhost). Confirm the right port (3306) is used and allowed.
Also, test connectivity from inside your backend container to the database. If it still times out, check Railway’s network settings for your project.

sim
FREETop 1% Contributor

4 days ago

Without any sensitive details can you share your environment variable set up? I see you say you have them set up correctly but I am not able to deduce how they are set up

sim
FREETop 1% Contributor

4 days ago

The services within the same project will be able to connect using Railway private network https://docs.railway.com/guides/private-networking#communicating-over-the-private-network

sim
FREETop 1% Contributor

4 days ago

I have found this on another bounty that was responded to by @uzux who is a moderator https://station.railway.com/questions/internal-service-not-connecting-78a08b8e#h3vx

He says:

Hey, private networking is IPv6 only, did you make sure that your new service is also listening on IPv6? https://docs.railway.com/guides/private-networking

johnanderson5
FREE

3 days ago

Hi Guys thank you for the help I'm not sure what exactly fixed it, but it's working now. I made this change to address the IPv6 suggestion.

// Only add family: 0 if we're using Railway's MySQL host
if (process.env.MYSQLHOST) {
  poolConfig.family = 0; // Enable IPv6 support for Railway
}

And I also changed my docker file, one of those changes fixed the issue. Thank you!

heart2

johnanderson5

Hi Guys thank you for the help I'm not sure what exactly fixed it, but it's working now. I made this change to address the IPv6 suggestion.// Only add family: 0 if we're using Railway's MySQL host if (process.env.MYSQLHOST) { poolConfig.family = 0; // Enable IPv6 support for Railway }And I also changed my docker file, one of those changes fixed the issue. Thank you!

sim
FREETop 1% Contributor

3 days ago

Thanks for the update, it is great that IPv6 or the dockerfile change fixed the issue. If you don't mind me asking what was the docker file change? It will also help others

Persistent Network Connection Failure - Railway Help Station