Given the "bingbot" in user agent, when I do step 1 of verifying the bot, I do not get a proper hostname. Some IP lookup tools just return the IP address itself while some say "No valid reverse DNS data is received from host. Try again later." and others do not return any hostname at all.
So all the IPs in this subnet fail step 1 (reverse DNS check) and hence should be considered as someone spoofing? But then,