DNS
18 BADTIME
Signature out of time window. The TSIG signature timestamp is outside the allowed clock skew, indicating a time synchronization issue.
When You See This Code
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.