IODA monitors the Internet in near-realtime to identify macroscopic Internet outages affecting the edge of the network, i.e., significantly impacting a network operator (AS) or a large fraction of a country.

Interactive Interfaces

Advanced interface for exploratory analysis of all time series data generated by IODA. Allows researchers to build custom visualizations by composing time series together using specialized post-processing functions. (Requires an account)

Dashboard showing the raw outage alert feed generated by IODA.

Example Outages

Syria, Jun 2020 (Exam-related)

Government-ordered Internet shutdowns in conjunction with national exams have been occurring in Syria for several years. These shutdowns disconnect most of the country from the rest of the Internet. In this example from June 2020, IODA's data and visualizations clearly show the pattern of these outages.

West Africa, Jan 2020 (Cable cut)

On January 16 2020, undersea cable infrastructure problems severely disrupted Internet connectivity in several West African countries. IODA detected significant outages affecting the Republic of Congo, Namibia, the Democratic Republic of Congo, and Angola during this time.

Iran, Nov 2019 (Government-mandated)

Amid widespread protests against the government, on November 16 2019, Iran experienced one of the most severe government-ordered Internet outages. This detailed analysis shows how most Iranian users were affected for nearly a week. Amnesty International used IODA's data in an investigation correlating this Internet shutdown with the killing of hundreds of Iranians.

COOL-IDEAS (AS 37680), Sep 2019 (DDoS attack)

A distributed denial-of-service (DDoS) amplification attack leveraging the DNS and CLDAP protocols and using the "carpet bombing" approach resulted in a multi-hour Internet outage for South Africa's largest Internet service provider on September 21 2019.

China, May 2019

On May 13 2019, IODA detected a significant Internet outage affecting China that began at 7:30 PM UTC and continued for several hours. The outage was reported by several sources, including ThousandEyes and InternetIntelligence but its cause remains unclear.

Venezuela, Mar 2019 (Power outage)

In March 2019, Venezuela was affected by several power outages. IODA's data also shows the cascading failures affecting the power grid as repeated efforts at restoration obtained temporary success.

CenturyLink (AS209), Dec 2018 (Network misconfiguration)

In late December 2018, IODA detected a large-scale Internet outage affecting CenturyLink, a major residential Internet Service Provider (ISP) in the U.S. The outage lasted for more than a day and reportedly affected millions of users and was caused by "malformed management packets", according to an FCC report.

Iraq, Oct 2016 (Exam-related)

In the first week of October 2016, IODA detected nearly daily outages that significantly affected Iraqi Internet connectivity.

Gabon, Sep 2016 (Government-mandated)

In early September 2016, IODA detected daily outages in Gabon that significantly affected Internet connectivity. These outages were widely reported (e.g., by CNN, Cloudflare, Akamai, etc.) and were "initially imposed amid clashes between opposition protesters and security forces following the announcement that incumbent President Ali Bongo had won reelection by a slim margin".


IODA combines information from three data sources, establishes the relevance of an event and generates alerts. The outage events and the corresponding signals obtained through automated analysis are displayed on dashboards and interactive graphs that allow the user to further inspect the data.

Global Internet routing (BGP)

We use data from ~500 monitors participating in the RouteViews and RIPE RIS projects to establish which network blocks are reachable based on the Internet control plane.

Internet Background Radiation

We process unsolicited traffic reaching the UCSD Network Telescope monitoring an unutilized /8 address block.

Active Probing

We continuously probe a large fraction of the (routable) IPv4 address space from CAIDA servers and use a methodology developed by University of Southern California to infer when a /24 block is affected by a network outage.

See the IODA project page for scientific references and for more information about our methodology.


This platform was supported by NSF grant CNS-1228994 [Detection and Analysis of Large-scale Internet Infrastructure Outages (IODA)].

This platform was supported by Department of Homeland Security Science and Technology Directorate (DHS S&T) contract 70RSAT18CB0000015 [IODA-NP: Multi-source Realtime Detection of Macroscopic Internet Connectivity Disruption], and DHS S&T cooperative agreement FA8750-12-2-0326 [Supporting Research and Development of Security Technologies through Network and Security Data Collection].

This platform was supported by the Open Technology Fund under contract number 1002-2018-027.

Additional funding to work on visualization interfaces was generously provided by a Comcast research grant.

Additional funding to support this platform was generously provided by a grant from the Internet Society.

See the Acknowledgements page for more support information.