Niruddha

A data-driven DNS monitoring project documenting resolution behavior across Indian ISPs.

Background

There is no comprehensive public record of DNS-level filtering in India.

DNS resolution behavior varies across Indian ISPs. A domain that resolves normally on one provider may return a filtered response on another. These differences are not systematically documented in any public dataset.

Niruddha (निरुद्ध, "obstructed" in Sanskrit) addresses this gap by continuously resolving domains against ISP nameservers and recording the results. The project provides a structured, queryable record of observed filtering behavior.

What We Measure

DNS resolution outcomes across six major Indian ISPs.

The project tests over 28 crore domains sourced from CZDS and Certificate Transparency logs, generating more than 100 crore DNS responses to date. For each domain, the system records:

Resolution outcome per ISP resolver (ACT, Airtel, Jio, BSNL, Idea, Tata)
Filtering indicators such as sinkhole addresses and non-standard responses
Cross-provider differences in resolution behavior for the same domain
Editorial context including related articles, notes, and observation dates

Resolution Differences

Filtering behavior varies across providers.

These differences are observable across several dimensions:

Scope: The number of filtered domains differs between providers
Overlap: Not all providers filter the same set of domains
Method: Filtering mechanisms vary at the DNS response level

Niruddha records these differences without interpreting their cause. The dataset is available for researchers, journalists, and the public to examine independently.

Methodology

Domains are resolved continuously and automatically against ISP nameservers using ZDNS. Responses are compared against known filtering indicators: sinkhole addresses, NXDOMAIN overrides, and non-standard replies.

The project documents its methods and known limitations. For technical details, see the Infrastructure page.

Browse the Dataset