Usually when you dial in or connect up, you are allocated an address. when they are Dynamically allocated, you get a different one almost every time. hence if someone has been a bad boy, you may see these messages.
Consider an ISP with 2 million customers, but who only have 200,000 on line at anyone time, ie people at work, school etc are not at home and using their PCs etc.
Why (form the ISP's point) would you need to buy 2 million IP addresses, when you only need 200,000, despite having 2 million customers. You dish them out as your customers log in, and re-use them agin for the next customer loggin in.
Unless you are running a Website, or mail server or a Domain you dont really need a fixed address.
This is mainly the reasons behind it all.
Some pratt is a naughty boy, the IP address gets black listed, then he logs off, you log on, and get allocated his old address, and pick up the blacklisting when you try to access the same site etc. Its not your fault, and you can easily prove it wasnt you, as the IP address was banned say at 10:00, but you didnt log in and get it allocated to you until 10:30..
It shouldnt be a major problem..
