Where do geo-ip SaaS get their data from?

Question

Geolocation

1) Where do they get the base of ip-shniks, access to which is then provided for money?
2) IP by geo binding can change? for example, did one ip belong to one country or city, and next month to another?

Answer 1

1) j.mp/2qUNVhb
2) can. but this is not practiced very often.

Answer 2

1) https://habrahabr.ru/post/227183/ is popular here, initially everything is from IANA
2) not next month, but generally they can, this is especially clearly expressed by ATT and other global providers, the same Akamai, hosters etc.), mobile operators

Answer 3

2) Provider Ukrtelecom - by IP address, you can only accurately determine that this is Ukraine. The same IP can be issued even to Kiev, even to Odessa (500 km difference) and such a change occurs after the modem is turned on / off, roughly speaking once a day.
At the same time, HTML5 Geolocation very often shows up to the house, if you need accuracy, better use the latter.
PS: You can change both.