http_proxy=http://proxy.example:8080 https_proxy=http://proxy.example:8080 podman build --http-proxy=true -t app:local .

--http-proxy defaults to true. It forwards the documented HTTP, HTTPS, FTP, all-proxy and bypass variables, including uppercase forms, when they exist in the relevant build environment.

InputEffect
--http-proxy forwardingProxy input for build steps
podman build --envEnvironment values retained in the resulting image

For public build-step downloads where public proxies are permitted, the HTTP proxy list supplies candidates for the example HTTP proxy URLs. For a remote client, forwarding reads the Podman server process's environment. A value set only in the laptop shell may not reach that builder.

A Containerfile can override a forwarded value, and the RUN downloader still must support it. Image retrieval before RUN uses the image-pull client's route; an export inside a later step cannot repair that earlier failure.

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