1DNSTRACER(8)                General Commands Manual               DNSTRACER(8)
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NAME

6       dnstracer - trace a chain of DNS servers to the source
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SYNOPSIS

9       dnstracer [options] name
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DESCRIPTION

12       dnstracer determines where a given Domain Name Server (DNS) gets its
13       information from, and follows the chain of DNS servers back to the
14       servers which know the data.
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16       Options are:
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18       -c      Disable local caching.
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20       -C      Enable negative caching.
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22       -o      Enable overview of received answers at the end.
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24       -q queryclass
25               Change the query-class, default is A. You can either specify a
26               number of the type (if you're brave) or one of the following
27               strings: a, aaaa, a6, soa, cname, hinfo, mx, ns, txt and ptr.
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29       -r retries
30               Number of retries for DNS requests, default 3.
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32       -s server
33               DNS server to use for the initial request, default is aquired
34               from the system. If a dot is specified (.), A.ROOT-SERVERS.NET
35               will be used.
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37       -v      Be verbose on what sent or received.
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39       -4      Use only IPv4 servers, don't query IPv6 servers (only available
40               when IPv6 support hasn't been disabled)
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42       -S sourceaddress
43               Use this as source-address for the outgoing packets.
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HOW IT WORKS

46       It sends the specified name-server a non-recursive request for the
47       name.
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49       Non-recursive means: if the name-server knows it, it will return the
50       data requested. If the name-server doesn't know it, it will return
51       pointers to name-servers that are authoritive for the domain part in
52       the name or it will return the addresses of the root name-servers.
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54       If the name server does returns an authoritative answer for the name,
55       the next server is queried. If it returns an non-authoritative answer
56       for the name, the name servers in the authority records will be
57       queried.
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59       The program stops if all name-servers are queried.
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61       Make sure the server you're querying doesn't do forwarding towards
62       other servers, as dnstracer is not able to detect this for you.
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64       It detects so called lame servers, which are name-servers which has
65       been told to have information about a certain domain, but don't have
66       this information.
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EXAMPLES

69       Search for the A record of www.mavetju.org on your local nameserver:
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71       dnstracer www.mavetju.org
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73       Search for the MX record of mavetju.org on the root-nameservers:
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75       dnstracer "-s" . "-q" mx mavetju.org
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77       Search for the PTR record (hostname) of 212.204.230.141:
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79       dnstracer "-q" ptr 141.230.204.212.in-addr.arpa
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81       And for IPv6 addresses:
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83       dnstracer "-q" ptr "-s" . "-o"
84       2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.6.4.0.2.0.0.0.0.8.b.0.e.f.f.3.ip6.int
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SEE ALSO

87       ntptrace(8), traceroute(8), dig(1)
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AUTHOR

90       Edwin Groothuis, edwin@mavetju.org (http://www.mavetju.org)
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92       See http://www.mavetju.org/contacts.php for mailing-lists.
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96February 10, 2008              February 10, 2008                  DNSTRACER(8)
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