API Reference DNS v0.2.3
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DNS Class
Note
As noted in [RFC6762], Multicast DNS can only carry DNS records with classes in the range 0-32767. Classes in the range 32768 to 65535 are incompatible with Multicast DNS. But Multicast DNS uses the 32768(0x8000) as a special value to indicate a cache-flush request.
DNS Message
All communications inside of the domain protocol are carried in a single format called a message. The top level format of message is divided into 5 sections (some of which are empty in certain cases) shown below
DNS Domain
EDNS0 moudle
EDNS0 is defined in RFC6891
DNS EDNS0
DNS COOKIE Option
The DNS COOKIE option is an OPT RR [RFC6891] option that can be included in the RDATA portion of an OPT RR in DNS requests and responses. The option length varies, depending on the circumstances in which it is being used. There are two cases, as described below. Both use the same OPTION-CODE; they are distinguished by their length.
DNS EDNS0 Option Codes (OPT)
DNS Header
The header contains the following fields
DNS OpCode
OpCode Name Reference
0 Query [RFC1035]
1 IQuery (Inverse Query, OBSOLETE) [RFC3425]
2 Status [RFC1035]
3 Unassigned
4 Notify [RFC1996]
5 Update [RFC2136]
6 DNS Stateful Operations (DSO) [RFC8490]
7-15 Unassigned
Reference
DNS Question
DNS RCode
DNS return code
Record is a struct that represents a DNS resource record.
DNS RRTypes
DNS Resource Record Type