Fixed a bug w/ comodo.

dns_compare.py

@@ -3,6 +3,7 @@
 import argparse
 import json
 import os
+import sys
 import time
 from datetime import datetime
 from concurrent.futures import ThreadPoolExecutor
@@ -37,6 +38,7 @@ parser.add_argument('--records', nargs='*', help='Hostname(s) to query. If not p
 parser.add_argument('--record-type', default='A', help='DNS record type to query. Default: A')
 parser.add_argument('--threads', type=int, default=None, help='Number of threads to use for queries. Default: CPU count - 1')
 parser.add_argument('--timeout', type=float, default=5.0, help='DNS query timeout in seconds. Default: 5.0')
+parser.add_argument('--verbose', action='store_true', help='Enable verbose debugging output.')
 parser.add_argument('--list-record-types', action='store_true', help='Print list of supported record types and exit.')
 args = parser.parse_args()
 
@@ -97,12 +99,36 @@ def perform_query(full_domain, ns, record_type, timeout):
         qname = name.from_text(full_domain)
         q = message.make_query(qname, record_type)
         
-        # Try UDP first
+        # Add EDNS0 extension for better compatibility (like dig does)
-        r = query.udp(q, ns, timeout=timeout)
+        q.use_edns(edns=0, ednsflags=0, payload=4096)
         
-        # If truncated, retry with TCP to get all results
+        # Try TCP first for better compatibility with some servers
-        if r.flags & flags.TC:
+        try:
             r = query.tcp(q, ns, timeout=timeout)
+            if args.verbose:
+                print(f"[DEBUG] TCP Response: Answer={len(r.answer)} RRsets, TC flag: {bool(r.flags & flags.TC)}", file=sys.stderr)
+        except Exception as e:
+            # Fall back to UDP if TCP fails
+            if args.verbose:
+                print(f"[DEBUG] TCP failed ({e}), trying UDP...", file=sys.stderr)
+            r = query.udp(q, ns, timeout=timeout)
+            
+            # If UDP returns truncated, retry with TCP
+            if r.flags & flags.TC:
+                if args.verbose:
+                    print(f"[DEBUG] UDP Response truncated (TC flag set), retrying with TCP...", file=sys.stderr)
+                r = query.tcp(q, ns, timeout=timeout)
+                if args.verbose:
+                    print(f"[DEBUG] TCP Retry Response: Answer={len(r.answer)} RRsets, TC flag: {bool(r.flags & flags.TC)}", file=sys.stderr)
+        
+        # Verbose debugging
+        if args.verbose:
+            print(f"\n[DEBUG] Query: {full_domain} (@{ns}) Type: {rdatatype.to_text(record_type)}", file=sys.stderr)
+            print(f"[DEBUG] Response code: {rcode.to_text(r.rcode())}", file=sys.stderr)
+            print(f"[DEBUG] Answer section: {len(r.answer)} RRsets", file=sys.stderr)
+            print(f"[DEBUG] Authority section: {len(r.authority)} RRsets", file=sys.stderr)
+            print(f"[DEBUG] Additional section: {len(r.additional)} RRsets", file=sys.stderr)
+            print(f"[DEBUG] Full message: {r}", file=sys.stderr)
         
         # Check response code
         response_rcode = r.rcode()
@@ -111,14 +137,35 @@ def perform_query(full_domain, ns, record_type, timeout):
             return (full_domain, ns, f"RCODE: {rcode_name}")
         
         results = []
+        
+        # Check answer section first
         answers = r.answer
         if answers:
             for rrset in answers:
                 for item in rrset:
                     results.append(str(item))
-        else:
+            return (full_domain, ns, results)
-            # No answer records returned (NODATA)
+        
-            return (full_domain, ns, "NO RECORDS")
+        # If no answer, check additional section (some servers put records there)
+        additional = r.additional
+        if additional:
+            for rrset in additional:
+                for item in rrset:
+                    results.append(str(item))
+            if results:
+                return (full_domain, ns, results)
+        
+        # If still no results, check authority section
+        authority = r.authority
+        if authority:
+            for rrset in authority:
+                for item in rrset:
+                    results.append(str(item))
+            if results:
+                return (full_domain, ns, results)
+        
+        # Truly no records found
+        return (full_domain, ns, "NO RECORDS")
         
         return (full_domain, ns, results)
     except (exception.Timeout, TimeoutError):