It has been observed for some time that some of our site visitors, usually of the less desirable types have been ‘presenting’ Private IP addresses, as reported by our site protection software.
An IP address is considered private if the IP number falls within one of the IP address ranges reserved for private uses by Internet standards groups. These private IP address ranges exist:
10.0.0.0 through 10.255.255.255169.254.0.0 through 169.254.255.255 (APIPA only)
172.16.0.0 through 172.31.255.255
192.168.0.0 through 192.168.255.255
Private IP addresses are typically used on local networks including home, school and business LANs including airports and hotels.
Devices with private IP addresses cannot (?) connect directly to the Internet. Likewise, computers outside the local network cannot connect directly to a device with a private IP. Instead, access to such devices must be brokered by a router or similar device that supports Network Address Translation (NAT). NAT hides the private IP numbers but can selectively transfer messages to these devices, affording a layer of security to the local network.
Standards groups created private IP addressing to prevent a shortage of public IP addresses available to Internet service providers and subscribers.
Despite the above, which is standard(?) Internet criteria, we have observed visitors using addresses in the 192.168 range for over a year. However since the beginning of the month (February 2014) we have seen a large number of addresses in the 172.16 range as well. Something has obviously changed as these should not be possible.
Searching on the web, has not revealed any other site that reported the problem? Whilst not an issue for ourselves, since we do not use the IP address information for any purpose other than providing an assessment of where our visitors original from, it might well pose a problem for other sites. It is suspected that the only ‘real’ way to stop the practise would be to block the IP ranges, such that a visitor using an IP address from outside the local network, that has a value within the ranges, being effectively ‘blocked’ from accessing any information upon a site, although this should not, according to the criteria above be required.