What it means in this context is that those IP Addresses:
17.172.34.9
17.172.34.11
17.172.34.65
do not have valid PTR records configured in DNS.
What it means in this context is that those IP Addresses:
17.172.34.9
17.172.34.11
17.172.34.65
do not have valid PTR records configured in DNS.