Publications Technical Report

New tech report “Identifying and Characterizing Anycast in the Domain Name System”

We just published a new technical report “Identifying and Characterizing Anycast in the Domain Name System” (available at .

From the abstract:

Since its first appearance, IP anycast has become essential
for critical network services such as the Domain Name Sys-
tem (DNS). Despite this, there has been little attention to
independently identifying and characterizing anycast nodes.
External evaluation of anycast allows both third-party audit-
ing of its benefits, and is essential to discovering benign mas-
querading or hostile hijacking of anycast services. In this
paper, we develop ACE, an approach to identify and charac-
terize anycast nodes. ACE first method is DNS queries for
CHAOS records, the recommended debugging service for
anycast, suitable for cooperative anycast services. Its second
method uses traceroute to identify all anycast services by
their connectivity to the Internet. Each individual method
has ambiguities in some circumstances; we show a com-
bined method improves on both. We validate ACE against
two widely used anycast DNS services that provide ground
truth. ACE has good precision, with 88% of its results corre-
sponding to unique anycast nodes of the F-root DNS service.
Its recall is affected by the number and diversity of vantage
points. We use ACE for an initial study of how anycast is
used for top-level domain servers. We find one case where
a third-party server operates on root-DNS IP address, mas-
querades to capture traffic for its organization. We also study
the 1164 nameserver IP addresses used by all generic and
country-code top-level domains in April 2011. This study
shows evidence that at least 14% and perhaps 32% use any-

Citation: Xun Fan, John Heidemann and Ramesh Govindan. Identifying and Characterizing Anycast in the Domain Name System. Technical Report N. ISI-TR-671, USC/Information Sciences Institute, June, 2011.

Data from this paper will be available from PREDICT through the LANDER project; contact the authors for details.