"Network Internet Data Transfer Out from Iowa to Apac(Excluding Korea and Indonesia)" cost

[JPP5]

Since February, the SKU Network Internet Data Transfer Out from Iowa to Apac (Excluding Korea and Indonesia) has been charged in my Project, this being traffic that we do not know where it comes from.  We have not made any changes to our application.

Firewall rules were added to reject both entry and exit from the APAC, but still that charge is increasing. We also block traffic with Cloudflare, only allowing traffic from Argentina.
The cost is exceeding 500 dollars per month, which represents a lot of cost for our company. 

Looking at the network topology, we observe that the vast majority is outgoing traffic (not direct internet traffic) from a VM that does not have a public IP, that only runs MySQL.

We contact support, but for months the only answer I have every week is:

Firstly, Apologies for any inconvenience. I understand that there is a delay for the update which is being billed for the services. I'm already following up with our internal teams, as there are multiple teams(Like the Network team and Engineering team) are involved to check for the root cause and to avoid this issue in future. And also checking to know whether the charges were incurred due to an error.

So I request you to wait for an update for 2-3 business days and I’ll keep you posted with an update

Any insight or direction would be greatly appreciated.

Thanks in advance.

[JPP5 · Accepted solution]

I finally managed to identify where that cost came from. It turns out that the server had a Snapshot scheduled daily as a backup, even though the Instance was in a region of the US, and that the Snapshot was in the US (several regions in the United States).

I redid the programming to match the region exactly and that SKU was no longer charged.

There was a Google error charging that SKU because it should never have sent traffic to APAC since both regions were US.

I hope this information is useful to someone.

Regards, JP