Short Answer:

We advise you to add both the IP address and domain/hostname associated to this IP address to be monitored by our platform (ie: 2 separated blacklist monitors, one for the IP address and another for the domain/hostname).

Longer Answer:

When adding new Blacklist Monitors to your HetrixTools account, you should note that our platform will only monitor what you’re telling it to monitor.

So if you add an IPv4 address, it will monitor that IP address, it will not automatically monitor the domain/hostname or the reverse DNS associated with that IP address, you would need to add this separately as a new blacklist monitor.

The vice versa scenario works as well, if you add a domain name to be monitored, you will also have to add its IP address(es) as separate blacklist monitors.

You can read the following article to learn how to add multiple blacklist monitors at once:
https://docs.hetrixtools.com/add-multiple-entries-at-once/

Why should I monitor both the IP address and the domain/hostname?

The answer is quite simple, because this is the best possible coverage you can get when monitoring blacklists. Either your IP or domain name might get blacklisted individually, unrelated one to the other, so it’s always best to monitor them both and know which one gets in trouble first.

Furthermore, domains get blacklist checked against domain specific blacklists, and IPs get blacklist checked against IPv4 specific blacklists, so when adding both your IP and your domain name you end up covering all of the blacklists that our system monitors.