About this site

This website is essentially just a set of tools that will ideally help to make sysadmin life a little easier. Ideally they can also help out others.

Most of the checks on this website that require DNS lookups will use Google's public DNS servers at & If you have recently made changes to your DNS configuration, I'd advise you to flush the Google DNS cache before performing any such tests (ie, the SPF Record Check or Reverse DNS Check) to ensure the best accuracy.

Some other checks may use cached data, ie the IP Address Lookup or the DNS Blacklist Check.

To help prevent abuse of this service, there are limits on the amount of requests you may make within a set period of time.

There is no guarantee towards the accuracy of results provided by, or to the availability of this service.

This service is provided "as is", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the service or the use or other dealings in the service.


November 2019
Removed MegaRBL.net from DNS blacklist check as domain has seemingly expired and is giving false positives
July 2019
Frontend updates
Added SMTP Server Test
9 Sept 2018
Total overhaul of website & updated API
31 Aug 2018
Removed the following from DNS Blacklist Check:
  • DRBL vote node dsbl.ru
  • DRBL work node dsbl.ru
  • RBL.JP all
  • RBL.JP short
  • RBL.JP virus
  • Rymsho's DNSBL
  • TornevallNET DNSBL
22 May 2017
Removed the following from DNS Blacklist Check:
  • mailhosts.org
  • Woody's SMTP Blacklist IPv4
  • Spam Grouper
  • Rizon RBL/DNSBL
  • emailbasura.org
  • AntiCaptcha.NET IPv4