DNS 3 NXDOMAIN vs 18 BADTIME
Both DNS 3 (NXDOMAIN) and 18 (BADTIME) belong to the DNS Response Codes (RCODEs) category. 3 indicates that non-Existent Domain. The queried domain name does not exist in the DNS namespace. Meanwhile, 18 means that signature out of time window. The TSIG signature timestamp is outside the allowed clock skew, indicating a time synchronization issue.
คำอธิบาย
Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
เมื่อคุณพบเห็น
The domain has no DNS records at all — either it was never registered, has expired, or you have a typo in the hostname.
วิธีแก้ไข
Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated.
คำอธิบาย
Signature out of time window. The TSIG signature timestamp is outside the allowed clock skew, indicating a time synchronization issue.
เมื่อคุณพบเห็น
The clocks on the DNS client and server are too far apart (usually more than 5 minutes), causing TSIG signature validation to fail.
วิธีแก้ไข
Synchronize clocks on both machines using NTP. Check that the TSIG fudge value (allowed skew) is reasonable — the default 300 seconds is usually sufficient.
ความแตกต่างหลัก
DNS 3: Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
DNS 18: Signature out of time window. The TSIG signature timestamp is outside the allowed clock skew, indicating a time synchronization issue.
You encounter 3 when the domain has no DNS records at all — either it was never registered, has expired, or you have a typo in the hostname.
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.
ควรใช้อันไหนเมื่อไร
For 3 (NXDOMAIN): Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated. 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.