Section: General Commands Manual (8)Updated: February 10, 2008Local indexUp
dnstracer - trace a chain of DNS servers to the source
dnstracer [options] name
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.
Disable local caching.
Enable negative 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, soa, cname, hinfo, mx, ns, txt and ptr.
Number of retries for DNS requests, default 3.
DNS server to use for the initial request, default is acquired from
the system. If a dot is specified (.), A.ROOT-SERVERS.NET will be
Be verbose on what sent or received.
Use only IPv4 servers, don't query IPv6 servers (only available
when IPv6 support hasn't been disabled)
Use this as source-address for the outgoing packets.
HOW IT WORKS
It sends the specified name-server a non-recursive request for the
Non-recursive means: if the name-server knows it, it will return
the data requested. If the name-server doesn't know it, it will
return pointers to name-servers that are authoritive for the domain
part in the name or it will return the addresses of the root
If the name server does returns an authoritative answer for the name,
the next server is queried. If it returns an non-authoritative
answer for the name, the name servers in the authority records will
The program stops if all name-servers are queried.
Make sure the server you're querying doesn't do forwarding towards
other servers, as dnstracer is not able to detect this for you.
It detects so called lame servers, which are name-servers which has
been told to have information about a certain domain, but don't
have this information.