Lol I hope u aren't confused by static dynamic public and private.

Static is fixed, that means u cut power unlimited times and reconnect unlimited time, u get the same ip, dynamic just all random. So if you own 123.123.123.123, u always get that number, u need to pay for static ip and they are expensive and will be more and more expensive. Normal Internet user get dynamic ip, each time they connect, they get different number. What is the different? If u have fix, u can host things, ppl know you are 123.123.123.123, ppl can directly find you. If dynamic, u tell your ip to somebody, the next time your router reboot or reconnect u get different, your old ip goes to somebody else. Check www.whatismyip.com

Private is internal ip, public is external, u cannot choose to have no public ip as others unable to send to your router, and u cannot choose to have no internal as your router unable to talk to you. So u don't have a choice, your data will use internal ip(LAN) until your gateway which also means your router, and your data will be using public ip to get out from the router, when responded by whatever server, they will use your public ip back to your router, and your router will use private ip(LAN) back to you.

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Added on June 14, 2012, 11:48 pmTo know your private or LAN ip type ipconfig in command prompt. To know your public ip just access www.whatismyip.com. And your 1st post is wrong. When u are have Internet connection means u got public ip d. And when the u got a router, that means u got a LAN. Missing any, u can't access Internet.