diff --git a/backend/scripts/p2-acceptance.mjs b/backend/scripts/p2-acceptance.mjs
index 3b3aacd0..3a7090e9 100644
--- a/backend/scripts/p2-acceptance.mjs
+++ b/backend/scripts/p2-acceptance.mjs
@@ -436,7 +436,7 @@ async function setupFixtures(ctx) {
         read_timeout_ms: 30001,
         max_bytes: 65536,
         max_redirects: 2,
-        allow_private_hosts: false,
+        allow_private_hosts: true,
         max_cache_bytes: 65536,
       },
     }),
@@ -765,6 +765,7 @@ async function writeInstallationFiles(ctx) {
     `THT_WS_P2_DWH_DWH_API_KEY_SOURCE=${ctx.secretPaths.dwh}`,
     `THT_WS_P2_DWH_EVIDENCE_SIGNED_URLS_SOURCE=${ctx.secretPaths.signed}`,
     `THT_WS_P2_FILESYSTEM_DWH_API_KEY_SOURCE=${ctx.secretPaths.filesystemDwh}`,
+    `THT_EVIDENCE_PRIVATE_HOST_ALLOWLIST=host.docker.internal`,
   ].join("\n") + "\n";
   await atomicWrite(operatorEnvPath, operatorEnv);
   await atomicWrite(join(ctx.run.root, "installation", "pi-auth.json"), JSON.stringify({ fixture: true }));
diff --git a/backend/src/workspace-maintenance.ts b/backend/src/workspace-maintenance.ts
index 4dce11c4..7de7a036 100644
--- a/backend/src/workspace-maintenance.ts
+++ b/backend/src/workspace-maintenance.ts
@@ -201,6 +201,8 @@ function createProductionService(): WorkspacePreprocessingService {
   });
   return new WorkspacePreprocessingService({
     dataRoot: config.dataRoot ?? "/data",
+    httpPrivateHostAllowlist: (process.env.THT_EVIDENCE_PRIVATE_HOST_ALLOWLIST ?? "")
+      .split(",").map((value) => value.trim()).filter((value) => value.length > 0),
     acquireActiveRuntime: async (workspaceId) => {
       const active = await renderActiveWorkspaceRuntime({
         workspaceId,