Are outbound requests sent from the instance's public IP?

[greg]

Alas … no. At least based on this thread. Check the replies from Jerome and Thomas:

Request: Fly IP ranges

What kind of IP restriction are you planning on adding? Filtering based on remote IP address? If that’s the case, our AS40509 IPs may not be the ones you see. You’ll most likely see each individual server’s IP addresses which aren’t assigned to our AS. Unfortunately that means there’s no specific range of IPs we can publish. We could publish each one of our IPs though . Will have to check with the team.

The closest thing would be to request the IPs a region uses. So if your app is in ams, you could get its current IP range. However the rather big flaw in that plan is that those IPs may change at any moment. See:

Request: Fly IP ranges

There are a lot of IPs these could be in Amsterdam, and they could change at any time. If it gets you unstuck you can use them but your life will be way easier if you find some other way to get this working. Right now they’ll need to allow: 104.225.98.0/24 145.40.96.0/24 147.75.85.0/24 104.225.98.0/24 147.75.87.0/24