walker(1): DNS zone using NXT/NSEC traversal

NAME

-y: Additionally perform verification on each RRset within the zone and print result of verification (in a zone file comment). This also turn on EDNS.0 and set the DNSSEC flag in queries.
-n: When querying for records, ask the nameserver non-recursively, instead of going through the full resolver logic. This parameter is useful when you know that the default name server (or the supplied specific nameserver) can respond correctly, which it typically only would if it is responsible for the zone.
The original motivation for the -n parameter was to improve speed when asking parents for NS records on delegated zones, which would make the server recursively ask the child servers.
-d: Enable debugging in the resolver (this will print all DNS packets, just like dig).
-x: Enable the EDNS.0 DNSSEC flag for SIG/RRSIG queries. Not effective if -y is used. This is needed for some servers to return SIG/RRSIG at all.
@nameserver: Query nameserver instead of the default nameserver.
zone: Name of the zone to retrieve master file for. For example, ``com''.
startname: Optional name to start the zone walk at. The default is to start walking from the start. This option is useful if the tool failed or was intterupted in the middle of a large zone.