Server error 500 and curl error

[myusernameisneeded]

Hello,

After installing the Heimdall Docker container on my Synology NAS, I quickly (within less than a minute) encountered an HTTP 500 error. The container log showed a cURL error 6:

cURL error 6: Could not resolve host: appslist.heimdall.site (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for https://appslist.heimdall.site/list.json

When I checked from the container console, DNS resolution failed, but it worked fine from my PC. It was there resolved using IPv6, while IPv6 is not supported in my Docker containers. That was the issue.

I managed to temporarily work around the issue by replicating /etc/hosts to the NAS folders and adding the following line to it:

185.199.111.153 appslist.heimdall.site

After restarting the container no more issue. It's been more than 30 minutes.

Maybe a fallback mechanism to IPv4 resolution in case of an error with IPv6 ?

I am not sure this is the right place to post this. Feel free to move/delete or let me know what to do.

[aptalca]

Maybe a fallback mechanism to IPv4 resolution in case of an error with IPv6 ?

I don't believe that has anything to do with the app or the container. The app simply does a curl call to that url. Whether it goes over ipv4 or ipv6 is all determined by your system, dns and your docker service.