diff --git a/Sandboxes/Proxy-domains.mdx b/Sandboxes/Proxy-domains.mdx
index 4295d70d..a5adf463 100644
--- a/Sandboxes/Proxy-domains.mdx
+++ b/Sandboxes/Proxy-domains.mdx
@@ -11,7 +11,7 @@ tag: "public preview"
 Domain filtering lets you control which external domains a sandbox can reach. You can define an allowlist (only listed domains are reachable) or a denylist (all domains except listed ones are reachable). Domain filtering and proxy routing are **independent configurations** — you do not need to duplicate domains across both. A domain can appear in the allowlist without having a proxy routing rule, and vice versa.
 
 <Warning>
-  Domain filtering relies on the sandbox's tools and libraries respecting the standard proxy environment variables (`HTTP_PROXY`, `HTTPS_PROXY`). Traffic from tools that ignore these variables will not be filtered. Routing-level enforcement is planned for a future release.
+  Domain filtering relies on the sandbox's tools and libraries respecting the standard proxy environment variables (`HTTP_PROXY`, `HTTPS_PROXY`). Traffic from tools that ignore proxy environment variables will not be filtered unless [domain filter enforcement](#domain-filter-enforcement) is enabled.
 </Warning>
 
 ## Allowlist
@@ -79,7 +79,45 @@ await SandboxInstance.create({
 </CodeGroup>
 
 <Note>
-  When both `allowedDomains` and `forbiddenDomains` are set, `forbiddenDomains` takes precedence: a domain that appears in both lists will be blocked.
+  When both `allowedDomains` and `forbiddenDomains` are set, `allowedDomains` takes precedence: a domain that appears in both lists will be allowed.
+</Note>
+
+## Domain filter enforcement
+
+By default, domain filtering depends on the sandbox's tools respecting `HTTP_PROXY` and `HTTPS_PROXY`. To enforce filtering even for tools that bypass those variables, add a `firewall` config with `rulesets: ["proxy"]`. This forces all outbound traffic to flow through the proxy at the network level.
+
+<CodeGroup>
+
+```typescript TypeScript
+await SandboxInstance.createIfNotExists({
+  name: "enforced-sandbox",
+  image: "blaxel/base-image:latest",
+  region: "us-was-1",
+  network: {
+    firewall: { rulesets: ["proxy"] },
+    allowedDomains: ["httpbin.org"],
+    proxy: { routing: [] },
+  },
+});
+```
+
+```python Python
+await SandboxInstance.create_if_not_exists({
+    "name": "enforced-sandbox",
+    "image": "blaxel/base-image:latest",
+    "region": "us-was-1",
+    "network": {
+        "firewall": {"rulesets": ["proxy"]},
+        "allowedDomains": ["httpbin.org"],
+        "proxy": {"routing": []},
+    },
+})
+```
+
+</CodeGroup>
+
+<Note>
+  Currently, this feature is not enforced automatically by the platform when a proxy is configured. In a future release, it will be automatically enforced whenever a proxy is configured.
 </Note>
 
 ## Firewall + proxy combined
diff --git a/Sandboxes/Proxy.mdx b/Sandboxes/Proxy.mdx
index b19e2867..1b270c06 100644
--- a/Sandboxes/Proxy.mdx
+++ b/Sandboxes/Proxy.mdx
@@ -92,9 +92,16 @@ sandbox = await SandboxInstance.create({
 | Field | Type | Description |
 |---|---|---|
 | `allowedDomains` | `string[]` / `list[str]` | Allowlist — only these domains are reachable. Supports wildcards (`*.s3.amazonaws.com`). |
-| `forbiddenDomains` | `string[]` / `list[str]` | Denylist — all domains except these are reachable. Supports wildcards. If both are set, `forbiddenDomains` takes precedence. |
+| `forbiddenDomains` | `string[]` / `list[str]` | Denylist — all domains except these are reachable. Supports wildcards. If both are set, `allowedDomains` takes precedence. |
+| `firewall` | `FirewallConfig` | Proxy firewall configuration. |
 | `proxy` | `ProxyConfig` | Proxy routing and bypass configuration. |
 
+### `FirewallConfig`
+
+| Field | Type | Description |
+|---|---|---|
+| `rulesets` | `string[]` / `list[str]` | Domain filtering rules to apply. Set to `["proxy"]` to force all sandbox outbound traffic through the Blaxel proxy. |
+
 ### `ProxyConfig`
 
 | Field | Type | Description |
diff --git a/changelog.mdx b/changelog.mdx
index 523d7b84..63f3d892 100644
--- a/changelog.mdx
+++ b/changelog.mdx
@@ -17,6 +17,14 @@ The SDKs can now clear a sandbox's expiration rules without recreating it. Pass
 
 <Update label="2026-06-13">
 
+### Proxy-based firewall support
+
+Sandboxes can now enforce domain filtering at the network level.
+
+</Update>
+
+<Update label="2026-06-13">
+
 ### Refreshed Billing Explorer experience
 
 <Frame>