internal/builder/builder.go

@@ -333,6 +333,9 @@ func one(ctx context.Context, run Runner, publish Publisher,
 			// it at that step and it is in no image layer. A Dockerfile that does not ask for it is
 			// unaffected; the secret is simply not read (novox/hq ADR 0076).
 			invocation = append(invocation, "--secret", "id=npmrc,src="+npmrc)
+			// Host network for the build, so a RUN reaching the package registry finds it where the
+			// binding says it is — the machine's own loopback, where the registry answers.
+			invocation = append(invocation, "--network", "host")
 		}
 		invocation = append(invocation, ".")
 		say("image", "docker build -f %s", a.From)
@@ -616,6 +619,8 @@ func publishPackage(ctx context.Context, run Runner, module, dir string, a catal
 	const within = "/app/module"
 	invocation := []string{
 		"run", "--rm",
+		// Host network, so the publish reaches the registry at the address the binding names.
+		"--network", "host",
 		"--volume", dir + ":" + within,
 		// Read-only, so a build cannot alter the credential, and at /root where npm reads it.
 		"--volume", npmrc + ":/root/.npmrc:ro",