`podman-build`: DNS lookup fails using `--net slirp4netns` (using `systemd-resolved` on the host) about buildah HOT 5 CLOSED

We just use the servers from /run/systemd/resolve/resolv.conf when systemd resolved is used.
The 10.0.2.3 address is the slirp4netns forward address. How does you /erc/resolv.conf sysmlink look like? If it is outside of /etc or /run it may not work correctly with slirp4netns

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➜ stat --format '%N' /etc/resolv.conf
'/etc/resolv.conf' -> '/run/systemd/resolve/stub-resolv.conf'

The container is successfully reading the stub file, which contains:

➜ rg --no-line-number -v '^#|^$' /etc/resolv.conf 
nameserver 127.0.0.53
options edns0 trust-ad
search lan

127.0.0.53:53 is...

➜ sudo ss -tulpn | awk '/127.0.0.53%lo:53/ {print substr($7, 10, 15)}'
systemd-resolve

and my systemd-resolved configuration contains:

➜ rg --no-line-number -v '^#|^$' /etc/systemd/resolved.conf.d/*.conf | head -n 3
[Resolve]
DNS=9.9.9.9#dns.quad9.net 149.112.112.112#dns.quad9.net 2620:fe::fe#dns.quad9.net 2620:fe::9#dns.quad9.net
FallbackDNS=1.1.1.1#cloudflare-dns.com 1.0.0.1#cloudflare-dns.com 2606:4700:4700::1111#cloudflare-dns.com 2606:4700:4700::1001#cloudflare-dns.com

We just use the servers from /run/systemd/resolve/resolv.conf when systemd resolved is used

This would appear to be an incorrect statement. As my original comment shows, buildah appears to be parsing my upstream resolvers (instead of just reading /run/systemd/resolve/resolv.conf), as well as the dns server dynamically fetched for my currently active non-loopback network interface (10.100.0.1).

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As said we only read /run/systemd/resolve/resolv.conf which always contains the upstream resolvers once we detect systemd-resolved is in use. It is completely impossible to use 127.0.0.53 as server in the container as this is a loopback address and nothing will be listening there in the container.

Did you verify which of these servers even work from the container?

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A friendly reminder that this issue had no activity for 30 days.

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Since we never heard back, closing.

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