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ASN and IP route lookup
Look up the autonomous system and announced route prefix for a public IP, or inspect information about an ASN using public routing data.
ASN & routes
Look up the autonomous system and announced route prefix for a public IP, or inspect information about an ASN using public routing data.
How to use this tool
Enter a public IPv4 or IPv6 address, or an autonomous system number such as AS13335. The result uses public routing information to relate an address to its announced prefix and originating network, with the source identified in the result.
Reading the results
An ASN describes a network participating in Internet routing; it does not identify an individual visitor. Routing observations can change and may differ across collectors. An address allocation, an announced route and the physical location of a server are separate facts.
Tools index
23 utilitiesDNS changes
Compare a saved DNS snapshot with a fresh lookup.
DNS lookup
A, AAAA, MX, TXT and other DNS records.
DNS comparison
Compare answers from two public resolvers.
WHOIS / RDAP
Domain and IP registration records.
Reverse DNS / PTR
Reverse DNS and forward-confirmed hostnames.
Sites on this IP
Find indexed domains sharing an IPv4 address.
Mail journey
Read the route and reported authentication of an email.
SPF map
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Email DNS
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SMTP check
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DKIM lookup
Public signing keys for a named selector.
Mail transport policies
MTA-STS policy and TLS reporting records.
Migration rehearsal
Check a new server before switching DNS.
IPv4 / IPv6
Compare a website over both address families.
Security contact
Find and review a site’s security.txt contact file.
Redirect trace
Follow the HTTP redirects of a web address.
Security headers
Review browser security policies in the response.
ASN & routes
Find the route prefix and autonomous system for an IP.
HTTP & TLS
HTTP headers and TLS certificate details.
TCP ping
Connection times on port 80 or 443.
Subnet calculator
Address ranges and subnet masks for IPv4 and IPv6.
My IP & connection
Your IP, network and proxy indicators.
DNS answers come from public resolvers. Registration data comes from the relevant registry. Results reflect the time and location of each check.
Visits and checks are recorded for site administration and abuse prevention.