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 188.8.131.52 & 184.108.40.206. 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.
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.