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IPv4 Routed /24 DNS Names Dataset
The IPv4 Routed /24 DNS Names dataset provides fully-qualified domain names for IP addresses seen in the traces of the IPv4 Routed /24 Topology Dataset.
We also provide the DNS query and response traffic resulting from the DNS lookups required to construct the DNS Names dataset.

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DNS names are useful for obtaining additional information about routers and hosts making up the Internet topology. For example, DNS names of routers often encode the link type (backbone vs. access), link capacity, Point of Presence (PoP), and geographic location. We have DNS Names data starting March 2008.

These datasets result from CAIDA's large-scale traceroute-based measurements running on the Archipelago (Ark) measurement infrastructure (also see CAIDA's Macroscopic Topology Project).

We perform these DNS lookups centrally at CAIDA using a custom-built bulk DNS lookup service. This service performs millions of DNS lookups per day. In general, we perform DNS lookups soon after we collect the topology traces so that the results better match the state of the Internet at trace collection time. However, to avoid undue load on remote DNS nameservers and to keep the daily lookup volume at a manageable level, we never perform a lookup for an address if we have successfully obtained a result in the preceding 7 days. Apart from this 7-day rule, we always perform a lookup whenever we encounter an IP address in traces. This means that we do repeat lookups at 7-day granularity for addresses that repeatedly occur in the traces. If the first attempt to look up a given IP address fails, then we retry up to two more times, waiting about one day between retries.

In addition to the DNS names we have in the past provided the daily trace files containing DNS query and response traffic resulting from these DNS lookups. This was discontinued in April 2014, because of a change in the data collection procedure. These traces capture the DNS traffic between our local recursive name server and global DNS servers (rather than the less useful final DNS results seen by DNS clients). These data are available in two forms: the most recent 30 days of DNS traffic files (i.e. from 30 days upto the current day); and a historic collection of DNS traces about three weeks long at quarterly intervals going back to July 2008. Traces are available in two formats: a standard pcap file, and a textual dump of each pcap file containing the most useful values from the DNS responses.

Data availability

  • Data older than one year is available as a public dataset. Access to these data is subject to the terms of the following CAIDA Acceptable Use Agreement (printable version in PDF format).

    When referencing this data (as required by the AUA), please use:
    The CAIDA UCSD IPv4 Routed /24 DNS Names Dataset - <dates used>,
  • Access to the most recent one year of data is provided through the website of the Information Marketplace for Policy and Analysis of Cyber-risk and Trust (IMPACT) and subject to the following:
    When referencing this data (as required by the TOU), please use:
    The CAIDA UCSD IPv4 Routed /24 DNS Names Dataset - < dates used >,, DOI 10.23721/107/1354085

Please, report your publications using this dataset to CAIDA.

Request Data Access

  • Access the publicly available CAIDA IPv4 Routed /24 DNS Names Dataset (and other topology data)
  • Request Access to the restricted CAIDA IPv4 Routed /24 DNS Names Dataset via IMPACT

Topology Datasets


For more information on CAIDA topology measurements, see:

For more information on topology measurements in general see:

  Last Modified: Thu Nov-14-2019 12:12:15 PST
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