diff --git a/routlin/maintenance.py b/routlin/maintenance.py
index 4bffc83..c2d1caa 100644
--- a/routlin/maintenance.py
+++ b/routlin/maintenance.py
@@ -540,8 +540,13 @@ ARP_MAX_AGE_SECS = 4 * 3600
 
 
 def refresh_arp_cache(cfg):
+    try:
+        with open(CONFIG_FILE) as f:
+            full_cfg = json.load(f)
+    except Exception:
+        full_cfg = {}
     vlan_networks = []
-    for v in cfg.get('vlans', []):
+    for v in full_cfg.get('vlans', []):
         subnet = v.get('subnet')
         mask   = v.get('subnet_mask')
         if subnet and mask: