I recently needed to configure the DNS records for a new micro-site domain we are launching soon. It can be a hit and miss process trying to get everything configured just right since every registrar is slightly different, and there are delays propagating the changes throughout the internet.
I’ve previously done searches to find online tools to help check this. But yesterday I talked to Google support, and they have their own tool for this. I’m most interested in their MX check and Dig DNS tools, but there are others on there as well. Looks pretty slick. I’m adding it to my repertoire. I recommend you do as well.