diff --git a/backend/app/services/device_discovery.py b/backend/app/services/device_discovery.py
index 6e8c406..f496fc9 100644
--- a/backend/app/services/device_discovery.py
+++ b/backend/app/services/device_discovery.py
@@ -507,7 +507,9 @@ async def discover_via_ssh(
             continue
 
         # Add the rack itself as a main_server device if it doesn't exist
-        logger.info(f"[ssh_discovery] Processing rack {rack_host} ({rack_name})")
+        # Use external_id (e.g., "lane-1-1") as the hostname
+        rack_hostname = external_id
+        logger.info(f"[ssh_discovery] Processing rack {rack_host} ({rack_hostname})")
         try:
             existing_rack = (await db.execute(
                 select(Device).where(
@@ -517,7 +519,6 @@ async def discover_via_ssh(
             )).scalar_one_or_none()
 
             if existing_rack is None:
-                rack_hostname = f"rack{rack_name}"
                 db.add(Device(
                     object_id=obj.id,
                     ip=rack_host,
@@ -552,7 +553,7 @@ async def discover_via_ssh(
             result.errors.append(f"Error adding rack {rack_host}: {exc}")
             result.actions.append(DeviceAction(
                 ip=rack_host,
-                hostname=f"rack{rack_name}",
+                hostname=rack_hostname,
                 action="ERROR",
                 reason=str(exc),
                 category="embedded",