IIJ Public DNS is a public recursive DNS resolver from Internet Initiative Japan Inc. (IIJ), one of Japan’s earliest commercial Internet service providers. It is open to anyone regardless of ISP and runs on IIJ’s domestic network.

The resolver accepts queries only over DNS over TLS (DoT) and DNS over HTTPS (DoH), so every lookup is encrypted in transit. Plaintext DNS is not offered.

On the privacy side, IIJ implements Query Name Minimisation, returns proper NXDOMAIN responses for non-existent names, and publishes a detailed account of what query data is collected and how long it is kept. The only filtering applied is DNS blocking for child sexual abuse material under standards set by the Internet Content Safety Association (ICSA). No malware or category filtering is layered on top.

Limitations

IIJ runs this resolver as a beta intended to validate DoT and DoH operations, so availability is not guaranteed and the service has a defined end date. It is not aimed at workloads that need an SLA or contracted support.

Endpoints:

• DoT: public.dns.iij.jp
• DoH: https://public.dns.iij.jp/dns-query