DNS 6 YXDOMAIN vs 19 BADMODE
Both DNS 6 (YXDOMAIN) and 19 (BADMODE) belong to the DNS Response Codes (RCODEs) category. 6 indicates that name Exists when it should not. Used in dynamic updates to indicate a name that should not exist already has records. Meanwhile, 19 means that bad TKEY Mode. The TKEY mode field contains a value not supported by the server.
Description
Name Exists when it should not. Used in dynamic updates to indicate a name that should not exist already has records.
When You See It
A DNS UPDATE prerequisite check failed because the domain name already exists when the update expected it to be absent.
How to Fix
Review your dynamic update prerequisites. If you expect to create a new name, remove the existing records first or change the prerequisite to allow existing names.
Description
Bad TKEY Mode. The TKEY mode field contains a value not supported by the server.
When You See It
Your client attempted a TKEY key exchange using a mode (e.g., Diffie-Hellman, GSS-API) that the server does not support or has not been configured for.
How to Fix
Check which TKEY modes the server supports and configure your client to use a compatible mode. GSS-TSIG (mode 3) is the most widely deployed.
Key Differences
DNS 6: Name Exists when it should not. Used in dynamic updates to indicate a name that should not exist already has records.
DNS 19: Bad TKEY Mode. The TKEY mode field contains a value not supported by the server.
You encounter 6 when a DNS UPDATE prerequisite check failed because the domain name already exists when the update expected it to be absent.
You encounter 19 when your client attempted a TKEY key exchange using a mode (e.g., Diffie-Hellman, GSS-API) that the server does not support or has not been configured for.
When to Use Which
For 6 (YXDOMAIN): Review your dynamic update prerequisites. If you expect to create a new name, remove the existing records first or change the prerequisite to allow existing names. For 19 (BADMODE): Check which TKEY modes the server supports and configure your client to use a compatible mode. GSS-TSIG (mode 3) is the most widely deployed.