What's the basic for compare source network names in firewall rules?

I want, that specific FQDN hosts, can't pass the firewall.
For that, I created a firewall rule with the action refuse (verwerfen).
Under source networks I put several FQDNs, which I don't want to pass the firewall. These FQDNs are reverse DNS names, which I got via nslookup!

I'm not an network specialist and so I have maybe a stupid question. 
The FQDNs names I have specified in this firewall rule, will be that compared also with the reverse DNS name or is it any other FQDN name, which can be different from the reverse DNS name?

Thanks for your support,
HGA