What is an IP and how to they work?What are IP's and how to do they work seem to be a question that surfaces a lot here on ProBoards Support. Let's start with what an IP actually is.
IP stands for Internet Protocol. An IP is a packet-based protocol for delivering data across networks. In simpler terms, an IP is a set of numbers assigned to your ISP account, not unlike a telephone number, or a license plate on a car. When sending data out to a server (Internet) your IP is included, kind of like how when calling someone on the telephone, your phone number is included on one's caller ID.
The IP identifies the location from which the information is being sent (ie; a server) Everyone posting here has an IP assigned to them.
Static IP'sA static IP means that your IP will remain the same each time you sign on to the Internet. This IP address will never change.
Dynamic IP'sA dynamic IP means that your IP may alternate each time you sign on to the Internet and you will end up with an IP address that has been used by others on your ISP. America Online is notorious for this, and often when assigning a new IP to a member who has signed on this may lead to problems of a member suddenly finding themselves banned, for no apparent reason, as a dynamic IP user is issued an IP that has been previously banned from the forum for another member's misconduct.
Dynamic IP's make it difficult to effectively ban members, because once they log back in, their IP may have changed slightly, which will allow them access to the forum again. This brings us to wildcard banning.
Wildcard BanningMost dynamic IP's only alternate through the last two numbers of the entire IP.
For example, lets say a member with the IP of 123.456.789.012 has caused trouble, and has been banned from the forum, so you ban the IP listed above. But the next day, their dynamic IP assigns them the IP of 123.456.789.013, they will now be free to come back, unbanned to the forum. A measure to prevent this is wildcard banning.
Instead of banning 123.456.789.012 you may want to ban 123.456.789.01* This way, no matter how many time their dynamic IP changes, the wild-card will keep them banned. However, if it changes slightly more, you may want to wildcard ban like 123.456.789.0*.*
Once in a while, their IP will change not only the last set of numbers, but the middle set as well, in which case you would want to wild-card ban like this: 123.456.***.*** however that is not recommended, as you may be inadvertently ban a lot of potential members from users of the same ISP.
The following has been contributed by
All Seeing EyesIn the UK we have several 'cheap' ISP services, they usually offer full speed for a set amount of time (maybe 1 month) then it goes down to 1/2 or 1/4 speed.
One place that offers this is a Supermarket chain, and users have shown to be using the same IP.
So here's my theory:
The cheap provider buys a router, connects it to the main provider, then sells the resulting shared connection, a bit like having several PC's at home like this.
The cheap provider might pay a higher price for the connection, but makes a lot more from reselling the connection to multiple users. Sometimes the main provider might also offer cheaper deals in the same way and because they are on the same router, they all have the same IP.
This has been a joint collaberation of xkamelx and All Seeing Eyes with a special thanks to ConqueringWolf 
