tunneling socket could not be established

Question

I have deployed node.js service on AKS which calls external api (cisco webex bot). But it throws error as

{"code":"ECONNRESET"}
2021-01-18T11:51:22.421Z [ [31merror [39m] [FAKEID] <../features/webhooks/incomingMessage.handler.js:31>tunneling socket could not be established, cause=getaddrinfo ENOTFOUND abc.proxy.abcd.com abc.proxy.abcd.com:8080

What would be the possible issue?

Answer 1

anonymous user, To better assist you on this issue, Just to confirm, is your app hosted on AKS or Azure App Service WebApp?

This could be due to SNAT Port exhaustion happening on your Node.js while connecting.
https://learn.microsoft.com/azure/load-balancer/load-balancer-outbound-connections#snat

On Azure App service - The SNAT port limit (128) affects opening connections to the same address and port combination.

Kindly see if implementing connection pool or scale-up App Service Plan tier (In case it is App Service) works.

Please check the 'Avoiding the problem' section in the document and let us know how it goes.