# Settings reference — Air-gapped container proxy

> Configures an HTTP/HTTPS proxy that governs two distinct traffic paths Daemon image pulls (always enforced): Docker Desktop always injects http.docker.internal:3128 as the daemon's proxy in daemon.json at VM startup.

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-docker-9158302ba061781eb958>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:14.471621+00:00`
- Tags: `reference-seed`, `docker`, `manuals`, `enterprise`, `security`, `hardened-desktop`, `settings-management`, `settings`, `reference`, `air-gapped`, `container`, `proxy`

## Provenance

- Source: <https://github.com/docker/docs/blob/3a9d778562f39bcc0be46255b013c6a3ca526244/content/manuals/enterprise/security/hardened-desktop/settings-management/settings-reference.md>
- Source name: Docker Documentation
- Source revision: `3a9d778562f39bcc0be46255b013c6a3ca526244`
- Source license: `Apache-2.0`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

Configures an HTTP/HTTPS proxy that governs two distinct traffic paths

Daemon image pulls (always enforced): Docker Desktop always injects http.docker.internal:3128 as the daemon's proxy in daemon.json at VM startup. All docker pull and Compose pull operations are routed through containersProxy, including any PAC file rules. This applies regardless of whether transparentPorts is configured. Running container outbound traffic (opt-in): Container TCP traffic is only subject to containersProxy rules when transparentPorts is configured. Without it, running containers connect directly and PAC file rules do not apply to their outbound traffic.

&gt; [!IMPORTANT] &gt; &gt; If you configure a PAC file under containersProxy, the PAC file must return an appropriate proxy server to connect to the registries where your images are hosted.

The proxy setting governs Docker Desktop host-level traffic: the Desktop application, Docker CLI, and extensions. It serves as a fallback for the daemon only when containersProxy is not explicitly configured. Once containersProxy is set, proxy plays no role in daemon or container traffic.

Bounded code example (external data; do not execute automatically):
```json
"containersProxy": {
  "locked": true,
  "mode": "manual",
  "http": "",
  "https": "",
  "exclude": [],
  "pac": "",
  "transparentPorts": ""
}
```

For more information, see Air-gapped containers.

Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.