It is common practice for operators of web services (e.g. web sites) to block IP addresses when there was malicious traffic originating from that address.

It is also common practice that internet users don't have a static IP address but get one assigned by their ISP via DHCP.

Now I would expect that it sometimes happens that a specific IP address gets banned from a service and later that address gets assigned to another user, leaving the new user (temporarily) banned from the service for no apparent reason. However, I never had this problem or heard of someone having that problem.

Does this sometimes happen? If not, what prevents this from happening?

closed as primarily opinion-based by Xavierjazz, DavidPostill, techraf, 3498DB, Ƭᴇcʜιᴇ007 Oct 25 '16 at 18:19

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    Yes it happens, and it becomes more of a problem with CGN because hundreds or thousands of users could be using the same public IPv4 address. – Ron Maupin Oct 22 '16 at 23:04

It happens frequently. It's happened to me. Websites ban IP addresses that post spam. Wikipedia blocks addresses of article vandalizers. DHCP addresses obtained from ISP are usually not very dynamic. My own connection typically has the same address for years.

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