dnstrace(1)                          General Commands Manual                          dnstrace(1)



NAME
       dnstrace - dns lookup tool


SYNOPSIS
       dnstrace t fqdn r


DESCRIPTION
       dnstrace  searches for all DNS servers that can affect the resolution of records of type t
       under the domain name fqdn, starting from the root server r.  You can list more  than  one
       root server.

       dnstrace uses the standard DNS resolution algorithm, but follows all possible paths in the
       algorithm.  It prints all responses it receives from DNS servers; it also prints  warnings
       about  slow servers, dead servers, misdelegated (``lame'') servers, and misformatted pack‐
       ets.  dnstrace is similar in spirit to DOC and dnswalk but is  much  more  effective  than
       those tools at debugging resolution problems.

       In  versions  1.03  and  above:  You  can pipe dnstrace through dnstracesort(1) for human-
       friendly output.  dnstrace can take a long time to run, so standard procedure is  to  save
       its output in a file:

         dnstrace any www.aol.com a.root-servers.net > AOL &

       Then you can run dnstracesort(1) to see the results so far:

         dnstracesort < AOL | less

       The  dnstracesort(1) output uses ul codes for boldface and underline; these codes are dis‐
       played properly by less(1).

       Beware that, as of January 2001, dnstrace produces more than 5 megabytes of output for the
       complete  trace  of  cr.yp.to starting from all the root servers.  It ends up sending more
       than 6000 queries to more than 200 different servers.


SEE ALSO
       dnsip(1), dnsipq(1), dnsmx(1), dnstxt(1), dnsqr(1), dnsq(1), dnsname(1), less(1), tinydns-
       get(1)

       http://cr.yp.to/djbdns.html



                                                                                      dnstrace(1)