Ubuntu Manpage: Net::DNS::RR::NSEC3 - DNS NSEC3 resource record

Provided by: libnet-dns-sec-perl_0.16-2_all

NAME

       Net::DNS::RR::NSEC3 - DNS NSEC3 resource record

SYNOPSIS

       "use Net::DNS::RR;"

DESCRIPTION

       Class for DNS Address (NSEC3) resource records.

       The NSEC3 Resource Record (RR) provides authenticated denial of existence for DNS Resource Record Sets.
       The NSEC3 RR lists RR types present at the NSEC3 RR's original ownername.  It includes the next hashed
       ownername in the hash order of the zone.  The complete set of NSEC3 RRs in a zone indicates which RRsets
       exist for the original ownername of the RRset and form a chain of hashed ownernames in the zone.

METHODS

ownername
Returns the hashed value of the original owner name as contained in the first label of the ownername of
the record.

The owner name for the NSEC3 RR is the base32 encoding of the hashed
owner name prepended as a single label to the name of the zone.

In other words the name(name) method returns the result of the ownername() method prepended to the name
of the containing zone.

optout
Reads and sets the opt-out attribute.

flags
Reads and sets the flag field.

hashalgo
Reads and sets the hashalgo (hash algorithm) attribute.

hnxtname
Reads and sets the hnxtname (hashed next ownername) attribute.

typelist (inhereted from NSEC)
print "typelist" = ", $rr->typelist, "\n";

Returns a string with the list of qtypes for which data exists for this particular label.

typebm (inhereted from NSEC)
print "typebm" = " unpack("B*", $rr->typebm), "\n";

Same as the typelist but now in a representation bitmap as in specified in the RFC. This is not the kind
of method you will need on daily basis.

covered, matched
print "covered" if $rr->covered{'example.foo'}

covered returns a nonzero value when the the domain name provided as argument is covered as defined in
the NSEC3 specification:

To cover: An NSEC3 RR is said to "cover" a name if the hash of the
name or "next closer" name falls between the owner name and the
next hashed owner name of the NSEC3. In other words, if it proves
the nonexistence of the name, either directly or by proving the
nonexistence of an ancestor of the name.

Similarly ismatched returns a nonzero value when the domainname in the argument matches as defined in the
NSEC3 specification:

To match: An NSEC3 RR is said to "match" a name if the owner name
of the NSEC3 RR is the same as the hashed owner name of that
name.

Functions

   name2hash
       Takes the hash identifyer (numeric), a fullyqualfied domain name, the number of iterations and a binary
       salt to compute the hash value used in the NSEC3 calculations.

           $hashalg=Net::DNS::SEC->digtype("SHA1");
           $salt=pack("H*","aabbccdd");
           $iterations=12;
           $name="*.x.w.example";

           $hashedname= Net::DNS::RR::NSEC3::name2hash($hashalg,$name,$iterations,$salt);
           print $hashedname;
       results in:
           92pqneegtaue7pjatc3l3qnk738c6v5m

       Normally the salt and itterations would be fetched from an NSEC3PARAM record.

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