diff --git a/scripts/roa.py b/scripts/roa.py
index 9248dc7..7f0bbcc 100755
--- a/scripts/roa.py
+++ b/scripts/roa.py
@@ -113,12 +113,13 @@ def neonet_get_asns():
             if not f.is_file():
                 continue
             fc = shell2dict(f.read_text())
-            present_keys = ('name', 'owner', 'desc')
+            present_keys = ('name', 'owner', 'desc', 'external')
+            required_keys = ('name', 'owner')
             asn = str2asn(f.name, 1)
             asns[asn] = {k: fc.get(k) for k in present_keys}
             assert fc.get('owner') in PEOPLE
-            for v in asns[asn].values():
-                assert v is not None
+            for k in required_keys:
+                assert asns[asn].get(k) # required fields missing
             assert AS_IS_NEONET(asn) or asns[asn].get('external')
         except Exception:
             print("[!] Error while processing file", f)