If an IP address is unassigned (not assigned to an internet-connected device), then we cannot take active measurements for it via our ProbeNet (Probe Network | IPinfo.io). In that case, we have to fall back to a record-based evidence for the location.
Even in those cases, we rely on the hierarchy of geolocation records. If the geofeed is available for the IP address, we will use that. If the geofeed is not available, we will use a number of WHOIS hints (ASN and IP ranges) and other record-based hints to choose from. We process about 70 different sources of location hints for our IP geolocation data.
For example, an IP address from 205.196.84.0/23 was recently assigned to a device. Through our traceroute and ping-based hints, we geolocated the IP address to Volico’s data center in Pompano Beach, FL.
Before that, when we did not have active measurement for the server, as it was device-assigned, we looked into our records.
The IP address was not associated with a geofeed. So, we cannot use the geofeed record.
The location hints we had were from the WHOIS ASN and the IP ranges themselves.
205.196.84.0/23 IP range details - IPinfo.io
The ASN WHOIS location was in Florida, and the IP ranges WHOIS location was in Cheyenne, Wyoming. We chose the range-based WHOIS Location for that IP address.
Our idea is to provide any information we have about the IP address. It is part of product design. In some cases, other IP geolocation providers will leave city, region, etc. fields empty, but we always try to find a location hint that we can map to city, zip code, etc.
We do not leave geolocation fields empty. Even if we cannot find any information on an IP address (which is very rare) we will fallback to the respective RIR’s office address as that indicates that the IP address has simply not been allocated to an organization which is a fair assumption of the location address.