1DNSTRACER(8)                  Additional Software                 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       -e      Disable EDNS0 options.
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24       -E size Set EDNS0 size, default is 1500 bytes.
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26       -o      Enable overview of received answers at the end.
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28       -q queryclass
29               Change the query-class, default is A. You can either specify a
30               number of the type (if you're brave) or one of the following
31               strings: a, aaaa, a6, soa, cname, hinfo, mx, ns, txt and ptr.
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33       -r retries
34               Number of retries for DNS requests, default 3.
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36       -s server
37               DNS server to use for the initial request, default is aquired
38               from the system. If a dot is specified (.), A.ROOT-SERVERS.NET
39               will be used.
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41       -v      Be verbose on what sent or received.
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43       -4      Use only IPv4 servers, don't query IPv6 servers (only available
44               when IPv6 support hasn't been disabled)
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46       -S sourceaddress
47               Use this as source-address for the outgoing packets.
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HOW IT WORKS

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

73       Search for the A record of www.mavetju.org on your local nameserver:
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75       dnstracer www.mavetju.org
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77       Search for the MX record of mavetju.org on the root-nameservers:
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79       dnstracer "-s" . "-q" mx mavetju.org
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81       Search for the PTR record (hostname) of 212.204.230.141:
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83       dnstracer "-q" ptr 141.230.204.212.in-addr.arpa
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85       And for IPv6 addresses:
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87       dnstracer "-q" ptr "-s" . "-o"
88       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.arpa
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SEE ALSO

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

94       Edwin Groothuis, edwin@mavetju.org (http://www.mavetju.org)
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96       See http://www.mavetju.org/contacts.php for mailing-lists.
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100June 10, 2008                    June 10, 2008                    DNSTRACER(8)