dnstracer(8)

NAME
dnstracer - trace a chain of DNS servers to the source

SYNOPSIS
dnstracer [options] hostname

DESCRIPTION
dnstracer determines where a given Domain Name Server (DNS) gets its information from, and follows the chain of DNS servers back to the servers which know the data.

Options are: Disable local caching. Enable overview of received answers at the end. Change the query-class, default is A. You can either specify a number of the type (if you're brave) or one of the following strings: a, aaaa, a6, cname, hinfo, mx, ns, txt. Number of retries for DNS requests, default 3. DNS server to use for the initial request, default is aquired from the system. If a dot is specified (.), A.ROOT-SERVERS.NET will be used. Timeout to wait for DNS answers, default 15 seconds. Be verbose on what sent or received.

HOW IT WORKS
It sends the specified DNS server a non-recursive request for the hostname.

Non-recursive means: if the DNS server knows it, it will return the data requested. If the DNS server doesn't know it, it will return pointers to DNS servers that are authoritive for the domain part in the hostname or it will return the addresses of the root DNS servers.

If the DNS server does have answers for the hostname, it is not further queried. If ther DNS server gave pointers to authoritive servers, these servers are queried.

The program stops if all servers are queried.

Make sure the server you're querying doesn't do forwarding towards other servers, as dnstracer is not showing this information to you.

SEE ALSO
ntptrace(8), traceroute(8), dig(1)

AUTHOR
Edwin Groothuis, edwin@mavetju.org (http://www.mavetju.org)

See http://www.mavetju.org/contacts.php for mailing-lists.

BUGS
If you are running dnscache of D. J. Bernstein on your local machine this program is useless. Dnscache ignores non-recursive requests.