Best guess, no actual check Rated 3 out of 5 stars

Not 100% bullet proof: If your host has IPv6 configured and the domain has IPv6 in DNS, but you are unable to connect (IPv6 tunnel issues, etc). This case it does not detect the fallback to IPv4 protocol.

This review is for a previous version of the add-on (0.6.5.1-signed). 

Hi Rick,
Thanks for your feedback. This is definitely a big limitation, I haven't been able to figure out a good way to get around this yet without having the addon actively try to communicate with the domain in question. Something to work on though!
Thanks,
Timothy