gistfile1.txt

   RFCs
   ====
   RFC 1035 : Domain names - implementation and specification, November 1987
   RFC 2181 : Clarifications to the DNS Specification, July 1997
        - defines an "RRSet" as combination of class, name and type.
        - deprecates differing TTLs within an RRSet, says should be treated as
          an error.
        - defines the "origin" as the child name just below the zone cut:
            "The name of the zone is the same as the name of the domain
             at the zone's origin."
        - mentions lack of authority over cutting NS records
        - specifies that the TTL is an unsigned number, but between 0 and
          2147483647 inclusive... if bit 31 is set, it must be regarded to be 0
        - clarifies CNAMEs...
        - labels... 1 - 63 bytes
        - FQDNs... 255 bytes incl separators.
        - clarifies that binary is cool.
        - the whole "name syntax" section is super important to ZFP
        
        "A DNS server may be
           configurable to issue warnings when loading, or even to refuse to
           load, a primary zone containing labels that might be considered
           questionable, however this should not happen by default."
   RFC 2308 :
        What the TTL field in SOA means, $TTL
   RFC 2540 :
        - $DATE
   RFC 2673  : Binary Labels in the Domain Name System, August 1999
        - Historic, not adopted. BIND errors on [bitstrings] in zone files now
   RFC 4027 : Domain Name System Media Types - 2005
        - Establishes "text/dns" as the zone MIME type.
        - Notes that " The encoding of detached DNS
            information is, unlike textual master files, well defined."
        - talks more about master file fugly and how using \DDD is recommended
        - "Interoperability considerations" on page 2, section 3
   RFC 3597 :   Handling of Unknown DNS Resource Record (RR) Types, Sep 2003
        - Section 5, 6... damn
        *********************************************
        *********************************************
   RFC 4343 : DNS Case Insensitivity Clarification, January 2006
       2.1.  Escaping Unusual DNS Label Octets... super useful
       "It is advisable to
       avoid using a backslash to quote an immediately following non-
       printing ASCII character code to avoid implementation difficulties."
       ... applies to all classes
       [4.2] "When a node in the DNS name tree is created by any of such
           inputs, no case conversion is done.  Thus, the case of ASCII labels
           is preserved if they are for nodes being created. "
       ... mentions RNAME case should be preserved because of foo in [email protected]
       "Further interoperability
           issues with unrecognized RR types exist, which may be handled as
           discussed in section 5 of RFC 3597 [8]."
           
    RFC 7553 wants quoted RDATA longer than 255 bytes (for URIs)
       
           
   Zone file notes, and differences between Bind and ldns.
   =======================================================
 - Parens *inside* tokens are allowed, e.g. "foo(bar". In Bind they effectively
   terminate the current token, and immediately start a second, producing
   "foo" & "bar". In essence, "foo(bar" is parsed like the same as "foo( bar"
   and "foo (bar"
   ldns, on the other hand, produces "foobar". The parens are omitted, and
   processed correctly as control characters, but only a single token is
   emitted.
   This means Bind will parse "foobar.com. A(8.8.8.8)", whereas ldns will
   treat "A8.8.8.8" as the record type.
 - ldns accepts tok"en, i.e. unescaped double quotes inside unquoted tokens.
 - Line breaks inside double quoted strings are treated differently.
   Neither require carriage returns to be escaped, even though Bind does
   parse zone files with CR line-endings, whereas ldns does not.
   Bind requires line-feeds to be escaped, ldns does not. ldns in fact
   randomly converts \n to a space (0x20).
   ldns also converts \r and \r\n to a space and double space, respectively.
   In Bind, a single slash cannot escape an entire \r\n sequence (presumably
   because the backslash needlessly escapes the carriage return, not the
   line-feed which actually needs escaping). I guess if you're on Windows
   and you want to create a TXT record containing a line  break, you have to
   go ahead and type "foo\013\010bar"
 - Both Bind and ldns allow '(' in column 0, but Bind then refuses
   to accept any form of whitespace to form the "previous name" placeholder.
   ldns will accept a space or tab, but not a lone line break. This is sort of
   unusual in that, elsewhere, when inside parens, line breaks (with or
   without an attached end-of-line comment) are treated as token delimiters.