DNS 協議字段解析結果rcode說明

Rcode	Name	Description	Reference
0	NoError	No Error	RFC1035
1	FormErr	Format Error	RFC1035
2	ServFail	Server Failure	RFC1035
3	NXDomain	Non-Existent Domain	RFC1035
4	NotImp	Not Implemented	RFC1035
5	Refused	Query Refused	RFC1035
6	YXDomain	Name Exists when it should not	RFC2136
7	YXRRSet	RR Set Exists when it should not	RFC2136
8	NXRRSet	RR set that should exist does not	RFC2136
9	NotAuth	Server Not Authoritative for zone	RFC2136
10	NotZone	Not AUthorized	RFC2845
11-15	Unassigned
16	BADVERS	Bad OPT Version	RFC6891
16	BADSIG	TSIG Signature Failure	RFC2845
17	BADKEY	Key not revognized	RFC2845
18	BADTIME	Signature out of time window	RFC2845
19	BADMODE	Bad TKEY Mode	RFC2930
20	BADNAME	Duplicate key name	RFC2930
21	BADALG	Algorithm not supported	RFC2930
22	BADTRUNC	Bad Truncation	RFC4635
23-3840	Unassigned
3841-4095	Reserved for Private Use
4096-65534	Unassigned
65535	Reserved