Blocked lookup

If you are getting a response of 127.255.255.255, the address you are querying from has been blocked for making too many requests.

Are you using a public DNS resolver?

Then you are sharing an address with thousands of other people, and the limit is shared with them. Run a local caching resolver and query us from it.

Are you hosting a lot of mailboxes?

We have to ask you to register to use our services. The rates are reasonable - we would like to keep serving you, but you are past what the free tier covers.

The current free limit is 100,000 lookups per day, per querying address. See the terms.