LDAPS is not a two-way authentication mechanism. PingConnect recommends limiting the IP range, but what about IP Spoofing?
IP Spoofing was fairly trivial with firewalls produced through the early 2000s, but modern firewalls are more capable of detecting and dropping malformed packets. With modern firewalls it is actually very difficult to spoof IPs without detection. We recommend reviewing the risk of IP Spoofing with your company’s firewall vendor.
