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chore: Listen on IPv6 by default #650

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chore: Listen on IPv6 by default #650

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4 changes: 3 additions & 1 deletion api/fly.toml
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Expand Up @@ -8,7 +8,9 @@ processes = []

[env]
PORT = "8080"
HOST = "0.0.0.0"
# Listen on IPv6 by default
# https://fly.io/docs/networking/private-networking/#listening-for-connections-on-6pn-addresses
HOST = "::"
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Should we listen on fly-local-6pn?

Your app’s service needs to bind to/listen on fly-local-6pn to be accessible via its 6PN address. For example, if you have a service running on port 8080, then you need to bind it to fly-local-6pn:8080 for it to be accessible to other Machines over the 6PN.

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Based on my understanding, this will break public access to this service via https://api.filspark.com.

See https://fly.io/docs/networking/app-services/#tl-dr

Screenshot 2025-06-24 at 08 44 21

https://fly.io/docs/networking/app-services/#a-note-on-ipv4-and-ipv6-wildcards

Services to be routed to using Fly Proxy need to bind to IPv4 addresses, and services to be reached over 6PN need to bind to IPv6, as described above. However, you may find that your service works even if you haven’t used the addresses we specified. IPv4-mapped IPv6 addresses, if enabled on the VM, can allow IPv4 (and thus Fly Proxy) connections to a service bound on [::]. Further, the wildcard syntax [::] or 0.0.0.0 sometimes covers both IPv4 and IPv6, depending on the language, library, or application.

Have you considered using Flycast private proxy instead of private networking? That would allow us to keep listening on IPv4.

https://fly.io/docs/networking/flycast/

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Alternatively, can we listen on both 0.0.0.0 and ::?

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I've taken a better look at the flycast and I think that would probably be a better solution. With flycast migration could be easier as we could setup the whole infrastructure to communicate over the private flycast address and once we're ready to migrate we can release our public IPs. 👍🏻

SENTRY_ENVIRONMENT = "production"
DOMAIN = "api.filspark.com"
REQUEST_LOGGING = "false"
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