IP address lookup and blocklist check
See your public IP address, then look up any IP address or domain: reverse DNS, forward-confirmed reverse DNS, network owner and ASN, and a check against a small set of public DNS blocklists.
What is my IP address
This calls this site's own address service, which reads the connection address to show it back to you. It is not stored or logged.
Browser details
Read from your browser on this page. Nothing here is sent anywhere.
Look up an IP address or domain
DNS names, including the address you enter, are sent from your browser to Cloudflare DNS over HTTPS, and the network owner lookup uses Team Cymru's DNS names through the same service, so those services can see the queried address. A domain is resolved to its A, AAAA and mail server (MX) addresses, up to 10. Blocklist checks are optional and described below.
Check mail servers takes a domain, finds its MX hosts and the single addresses in its SPF record, and checks those addresses against the blocklists. It always sends them to the blocklist API.
Network owner and country come from Team Cymru DNS data for the registry allocation of the address block. The country shows where the block was allocated, not where a device or user is, and no city-level information is given. Blocklist results come from a small fixed set of free lists. Not listed means only that a list that answered does not show the address; a list that refused or failed is shown as could not check. It is never a guarantee that an address is safe or that mail will be delivered.
Questions and answers
What is my IP address?
It is the public address your connection uses to reach websites. Your internet provider, workplace or VPN assigns it, and it can change. The answer at the top of this page is the address this site sees; a different network or VPN gives a different answer.
Is my IP address blacklisted?
Enter it above with the blocklist option on. The result covers only the few free lists named in the table, and only the ones that answered. Many other lists exist, and a list that is not shown can still affect your mail.
What does listed mean?
A list operator has recorded the address as a source of spam, abuse or compromise, or as a range that should not send mail directly. What that means for you depends on the list and on the receiver, because each receiver decides which lists it uses and how much weight to give them.
How do I get delisted?
Use the removal link in the table for that list. Fix the cause first, such as a compromised account or an open relay, or the address is likely to be listed again. Some listings, like SpamCop, expire on their own once reports stop. Addresses on a provider's range are often delisted through the provider.
Why does a PTR record matter for mail?
Receiving mail servers often look up the PTR record of the connecting address and expect the name to resolve back to the same address. A missing PTR record, or one that does not match, makes mail look suspicious. Only the owner of the address block can set it, usually your hosting or internet provider.