Capture of DNS statistics using dnscap and ithicap

Christian Huitema edited this page Mar 26, 2018 · 8 revisions

On Linux, building the tool produces not only the regular and the test executable, but also the Dnscap extension "ithicap" ( This can be used as any other Dnscap extension, as in:

dnscap -i <interface> -c 2000000 -w - | dnscap -r - -P /path/to/ -o <ithi-capture-file.csv>

The "-o" parameter specifies the output file, in CSV format. The "-P" parameter specifies the location of the "ithicap" extension; this depends on how you installed ithitools. The "-i" parameter points to the interface id, such as for example "eth0". The "-c" parameter directs dnscap to stop capture after a specified number of DNS packets.

Dnscap is maintained by DNS-OARC. One option is to clone and build from github. Another option is to get the tarball from DNS-OARC, and to follow the build step specified in the DNSCAP README on GitHub.

The list of ithicap parameters can be displayed by calling:

dnscap <dnscap-parameters> -P /path/to/ -h

At the time of this writing, this will display the following list:

ITHICAP -- a DNSCAP plugin for ITHI data extraction.
Usage: ithitools <options>
  -o file.csv        output file containing the computed summary.
  -r root-addr.txt   text file containing the list of root server addresses.
  -a res-addr.txt    allowed list of resolver addresses. Traffic to or from
                     addresses in this list will not be filtered out by the
                     excessive traffic filtering mechanism.
  -x res-addr.txt    excluded list of resolver addresses. Traffic to or from
                     these addresses will be ignored when extracting traffic.
  -f                 Filter out address sources that generate too much traffic.
  -n number          Number of strings in the list of leaking domains(M332).
  -t tld-file.txt    Text file containing a list of registered TLD, one per line.
  -u tld-file.txt    Text file containing special usage TLD (RFC6761).
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