DNS history of cirs.com.
Where a domain has pointed over the years: every address passive DNS saw, the network behind each one, and what it answers today.
Looking up…
How passive DNS works.
Sensors on participating networks note the DNS answers that resolvers receive: the name, the answer, and when it was first and last seen. Nothing is asked of the domain itself, so the history shows what people were actually sent. It only covers names those networks' users looked up.
Reading the timeline.
- Each step is a network (the company announcing the addresses) and the span its addresses were seen; a gap of over a year starts a new step.
- The network is the one that announces the address today. For cloud and hosting ranges that rarely changes, but an address can move to a new owner over the years.
- A very short period on an unexpected network is often a wrong answer from a filtering or hijacked resolver, not a real move.
- "Seen" counts how many times the sensors recorded the answer; busy sites reach millions.
Questions people ask.
What is DNS history?
A record of the answers a domain's DNS gave in the past: the IP addresses it pointed to, its aliases, and when. It comes from passive DNS, where sensors on networks note the answers resolvers receive and when each was first and last seen.
Where does the data come from?
From mnemonic's public passive DNS: records marked TLP:WHITE, which mnemonic offers to the public and which may be shared freely. Today's records come from live DNS, and the network behind each address from Team Cymru's IP to ASN mapping.
Why is my domain missing?
Passive DNS only sees names that the users of its sensors' networks look up. Small, new or rarely visited sites are often not in it, and that says nothing about the domain.
Does it show old name servers and mail servers?
Only what passive DNS saw, which is mostly addresses and aliases. For the registration record use WHOIS, and for old versions of the website the domain history tool.
Why does the history list a network the site never used?
Passive DNS records what resolvers were told, and filtering or hijacked resolvers sometimes answer with their own address. A short, isolated period on an unexpected network is usually one of those.
Hivex index
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More DNS tools
- DNS lookupAll records at once: A, AAAA, CNAME, MX, NS, TXT, CAA, SOA.
- MX lookupMail servers in priority order, the provider, SPF and DMARC at a glance.
- NS lookupName servers, the DNS host, SOA settings, and marketplace parking.
- TXT lookupSPF, DMARC, DKIM and verification tokens, joined and labelled.
- CNAME lookupThe full alias chain, the final addresses, and the platform behind it.
- CAA lookupAllowed certificate authorities, wildcard rules and report addresses.
- DNS propagation checker13 public resolvers side by side, with how long each keeps its copy.
- Reverse DNSThe PTR hostname of an IPv4 or IPv6 address, checked both ways.
- DNS health checkEvery name server asked directly: one report, every check.
- DNSSEC checkerDS, keys and validation: where the chain of trust holds or breaks.
- Subdomain finderSubdomains from certificate logs, DNS and the archive.
- DNS setup helperThe records each platform asks for, checked live.
- Domain checkerIs a name free to register? Checked live on any extension.
Sources
- mnemonic: the public passive DNS API
- mnemonic: passive DNS data offered to the public (TLP:WHITE)
- FIRST: the Traffic Light Protocol
- Team Cymru: IP to ASN mapping
By Hivex. Updated 11 October 2026. Past records come from mnemonic's public passive DNS and are kept up to a day; today's records are read live. The names you search are not stored.