Cloud Run URL Resolving to an IP that is Not Reachable

[tgtech]

I have a springboot web application deployed on cloud run and it's been running live on production for a few years.

cloud run instance url: https://myapp-prod-a7ow2sutca-de.a.run.app region: asia-east1

We also have a custom domain mapping: api.myapp.com -> https://myapp-prod-a7ow2sutca-de.a.run.app

Now we work with a payment gateway that will send us payment received notification via REST API and so we expose an endpoint api.myapp.com/payment-received that they will hit when a payment is received on the payment gateway's end.

Suddenly yesterday some notifications (intermittently) are missing and they told us that some of the requests sent out to api.myapp.com/payment-received were not getting any response. Further investigation led to api.myapp.com resolving to 74.125.68.121 which is not reachable (tried to ping it gives timeout). So requests coming out from one of their cluster always failed to reach us because api.myapp.com always resolved to this bad ip.

Then I created a new cloud run deployment api2.myapp.com in a different region and asked them to ping api2.myapp.com from their problematic cluster. And at first it resolves to a different ip address and it's pingable but after a few minutes it resolved back to 74.125.68.121 and not reachable again.

Other payment gateways are still working without a problem only this 1 payment gateway is giving this issue. They're claiming that it's Google Cloud's problem they are routing their requests to a bad IP.

We also have Cloudflare in front and they claimed that they have nothing to do with this, and confirmed that there's no configuration that will block certain IP's or anything weird.

What seems to be the problem here? Who should I contact in this case? It had been working for years just fine and suddenly this happened...

[princesslyca]

Hi @tgtech,

Welcome to Google Cloud Community!

There is a similar thread that can be found on another forum. As @Sai Chandra Gadde mentioned, it's a good idea to request them to double-check their settings to make sure there aren't any rules creating redirects or DNS issues. Another possibility is that the payment gateway is having DNS issues. You should try to request payment gateway to clear the DNS cache to see if that resolves the issue.

Hope this helps.