What are blacklists of IP addresses and what are the consequences if an IP address is blacklisted. Imagine yourself for a moment as a postman delivering mail to apartments in your area. Out of a thousand apartments, five are occupied by aggressive drug addicts who regularly attack postmen; After getting there a couple of times, you start to bypass these apartments.
You share this information with your fellow postmen, as well as with other services whose tasks include visiting apartments. For example, if the specialists in charge of checking the meters go to apartments without your blacklist, they will surely remember the meeting with drug addicts for a long time. And if they use your blacklist, they will bypass all the "dangerous" apartments. The situation is similar with IP addresses: there are companies that track IP addresses that carry out DDoS attacks, fraudulent activities, send spam, and add these addresses to their black lists.
And then other companies, mainly postal services, Internet providers, payment systems, banks, online stores, buy a check of the IP addresses of their visitors against these databases. For example, a buyer of an online store entered credit card information when paying for an item, the store checks if the user is on black lists. If an IP address is blacklisted, it is highly likely to be denied or sent for additional verification.
This is done because of the fraudsters who pay with stolen bank cards, whose victims are shops. I would like to note that in the case of checking and evaluating the user with modern anti-fraud systems, everything is somewhat more complicated than a simple check of the IP address in black lists, and the presence of an IP address in the black list is just one of the indicators that form the final user assessment. Therefore, getting an IP address on the blacklist is definitely bad, but "not critical".
A particular inconvenience for users of "dirty" IP addresses can be the constant introduction of captcha, for example, when using Google and Yandex search, passing checks from outside and anti-DDoS systems like CloudFlare. VPN users are particularly affected by this.
The IP addresses of public VPN services are regularly blacklisted due to the cybercriminals resorting to VPN services. If the IP address of the VPN server is blacklisted, then all users connected to this VPN server will have problems. I'll tell you a rather interesting case that happened to my acquaintance an expert in the field of IT security back in the middle of the two thousandth.
You, of course, will not be able to check in any way whether someone has previously committed any crimes from the IP address you received, but everyone can check the presence of an IP address in the black lists. Tip If you ever decide to use a public VPN or proxy service, check the IP address on site https://ip-locations.org/ for identified before using it. This also applies to a personal VPN or proxy, since hosting can provide you with a server with a "dirty" IP address. In this case, you need to contact your hosting provider and ask for a replacement. Remember that blacklists are not static and are constantly being updated.
He once consulted a user with an unusual request: the client claimed that his computer had been hacked and asked to find evidence of this. But the computer provided by the client did not show any signs of hacking, and my friend asked why the user had such confidence in hacking. It turned out that one of the local payment systems blocked his wallet with money, accusing him no less of carrying out attacks on the wallets of other users of the system.
A lot of money was blocked from him, but it was still in flower, as the representatives of the payment system planned to report the incident to the police to initiate a criminal case against the user. My friend spent a long time understanding the situation, communicating with the security service of the payment system and with the user, and in the end he got to the bottom of the truth. His client used a public proxy service, where he sat on the same server with an attacker who hacked accounts of the payment system. This is why their IP addresses were the same.
If someone else is using your IP address, your IP address can be blacklisted at any time. Today it can still be white and clean, and tomorrow it can be on all popular black lists. Another feature of blacklists that I would like to draw attention to is the relevance of the data. The IP address from which the illegal activity occurs is almost instantly listed. And if the illegal actions have stopped, then the IP address is excluded from the black list after a while, usually after 15-45 days.