More tidying up of some bugs.

dns_compare.py

@@ -9,6 +9,7 @@ from concurrent.futures import ThreadPoolExecutor
 from dns import message
 from dns import query
 from dns import rdatatype
+from dns import rcode
 from dns import name
 from dns import flags
 from dns import exception
@@ -103,12 +104,21 @@ def perform_query(full_domain, ns, record_type, timeout):
         if r.flags & flags.TC:
             r = query.tcp(q, ns, timeout=timeout)
         
+        # Check response code
+        response_rcode = r.rcode()
+        if response_rcode != 0:  # 0 = NOERROR
+            rcode_name = rcode.to_text(response_rcode)
+            return (full_domain, ns, f"RCODE: {rcode_name}")
+        
         results = []
         answers = r.answer
         if answers:
             for rrset in answers:
                 for item in rrset:
                     results.append(str(item))
+        else:
+            # No answer records returned (NODATA)
+            return (full_domain, ns, "NO RECORDS")
         
         return (full_domain, ns, results)
     except (exception.Timeout, TimeoutError):
@@ -184,8 +194,8 @@ for full_domain in full_domains:
             provider = nameserver_map.get(ns)
             if (full_domain, ns) in results_map:
                 results = results_map[(full_domain, ns)]
-                # Handle error/timeout cases (strings starting with specific markers)
+                # Handle error/timeout/rcode cases (strings)
-                if isinstance(results, str) and (results == "TIMED OUT" or results.startswith("ERROR:")):
+                if isinstance(results, str):
                     output[full_domain]["records"][provider][ns] = results
                 else:
                     results = sorted(results)
@@ -196,8 +206,8 @@ for full_domain in full_domains:
         for ns in all_nameservers:
             if (full_domain, ns) in results_map:
                 results = results_map[(full_domain, ns)]
-                # Handle error/timeout cases (strings starting with specific markers)
+                # Handle error/timeout/rcode cases (strings)
-                if isinstance(results, str) and (results == "TIMED OUT" or results.startswith("ERROR:")):
+                if isinstance(results, str):
                     output[full_domain]["records"][ns] = results
                 else:
                     results = sorted(results)