DNS 0 NOERROR vs 18 BADTIME
Both DNS 0 (NOERROR) and 18 (BADTIME) belong to the DNS Response Codes (RCODEs) category. 0 indicates that no error condition. The query completed successfully and the response contains the requested data. Meanwhile, 18 means that signature out of time window. The TSIG signature timestamp is outside the allowed clock skew, indicating a time synchronization issue.
Description
No error condition. The query completed successfully and the response contains the requested data.
When You See It
This is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
How to Fix
No fix needed. RCODE 0 means the DNS lookup succeeded as expected.
Description
Signature out of time window. The TSIG signature timestamp is outside the allowed clock skew, indicating a time synchronization issue.
When You See It
The clocks on the DNS client and server are too far apart (usually more than 5 minutes), causing TSIG signature validation to fail.
How to Fix
Synchronize clocks on both machines using NTP. Check that the TSIG fudge value (allowed skew) is reasonable — the default 300 seconds is usually sufficient.
Key Differences
DNS 0: No error condition. The query completed successfully and the response contains the requested data.
DNS 18: Signature out of time window. The TSIG signature timestamp is outside the allowed clock skew, indicating a time synchronization issue.
You encounter 0 when this is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
You encounter 18 when the clocks on the DNS client and server are too far apart (usually more than 5 minutes), causing TSIG signature validation to fail.
When to Use Which
For 0 (NOERROR): No fix needed. RCODE 0 means the DNS lookup succeeded as expected. For 18 (BADTIME): Synchronize clocks on both machines using NTP. Check that the TSIG fudge value (allowed skew) is reasonable — the default 300 seconds is usually sufficient.