diff --git a/src/services/headscale-adapter.ts b/src/services/headscale-adapter.ts
index 69bff97..8719846 100644
--- a/src/services/headscale-adapter.ts
+++ b/src/services/headscale-adapter.ts
@@ -115,6 +115,13 @@ export class HeadscaleAdapter {
         src: [groupName],
         dst: [`${ip}:*`],
       })
+      acls.push({
+        // ROS 2 DDS discovery and topic payloads also originate from the
+        // assigned platform, so keep the student workspace link bidirectional.
+        action: 'accept',
+        src: [ip],
+        dst: [`${groupName}:*`],
+      })
     })
 
     const policy: HeadscalePolicy = {