This may be the wrong forum, if so I apologize, didn't really know where it would fit.
Question -- is there some way to present a different IP address when loggine into a site?
Thanks for your help.

Thanks for your help.
Besides if it is possible... WHY would one want to do that?

Follow the same technique as with certain concealed email program software : find someone who is willing to receive and retransmit each of the packs of data from and to your computer, and forward to you from his/her computer as his/her own.
Whatever you do : your computer has to identify each of it's transmitted packs with an IP address, otherwise how would any reply to them ever reach you? All you can do is that your IP address is somewhere deleted and replaced with another IP address. For that you have providers like NO-IP.

Contact NO-IP and subscribe to do their services. (http://www.no-ip.com) There is even a limited free service!

Note that you ONLY insert NO-IP between you and the receiver/reader of your data. Security services will be able to find you through NO-IP if they have good reasons to do so (remember : you have to subscribe to NO-IP, and they have to know who you are to allow transfer of data from/to you.

Success!
As always : if you require more info, please let me know. If this solves your problem, please rate the answer provided! Feed back is always appreciated!
;)

First, to answer your question of why - nothing illegal or immoral. My wife and I play on-line poker (play money) and we would like to have separate logins. Since we play at different times of the day there is no conflict with our system. The problem is that some of the poker sites only allow one id. We have different E-Mails but that is not good enough, they look at the IP address and refuse to give us another login. So anyway, that's the why. I believe you have supplied the right answer, I'll give it a try. Thank you.

Another way is to reset your router by re-cycling power. Most ISP's will change your IP address when you do that. Check it by going to What Is My IP Address? - IP Address Lookup, Info, Speed Test, and more (http://whatismyip.com)

Ok, I went to the site "What's my IP, etc.". It tells me my IP address is one thing. However, this just leads to another question. If I display my IP address on my system via the control panel/internet connections it gives me something totally different. So why are they different? Do I have the IP for my system which is presented to my ISP but then it (my ISP) presents it's own IP address to the network? It should be pretty obvious by now that I am pretty dense about networks, thanks for your help.

I just did a power down/up and went back to "Whats my IP, etc.". It shows the same IP it did before.

Snowed (not in the literal sense) in MO.

You can try waiting a little longer. Say 10-15 minutes and see if it makes any difference.

I don't know if you have cable, DSL or FIOS.

There are a set of IP addresses which are called private. They are explained here. Private network - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Private_network)
Since there are not enough IP addresses to go around, a system has been developed toshare a public IP address.

Your private IP address likely begins with 192.168.

Now the tricky part. Within your network at home, all the IP addresses begin with 192.168 and so might your neighbors and so do many other people. It's common to assign an IP address of 192.168.0.1 to the router.

Addresses within your network can be dynamically or static. Static address are best used for printers, servers and access points. Dynamic addresses have a lease time assigned to them. When that time expires, it's likely that a new IP address will be assigned.

A laptop might be best served with a dynamic IP address because it can be used in a hotspot or home without any configuration changes.

If you wanted to run a webserver at home, you'd have to use the services of say DynDNS: Dynamic DNS, E-Mail Delivery and Other Services (http://www.dyndns.org) and run a program in your router or on another machine that will update the DNS (Dynamic Name Server) system at dyndns.org so that something like myhome. Dyndns. Org points to the address that whatismyip sees. Spaces added intentionally.

Furthermore, you have to tell your router what machine will respond to a "service". A "service" has what's called a default port associated with it. Port 80 is the default http or a web server which uses the HyperText Transfer Protocol

The router will then forward all incoming requests to port 80 on whatever static IP address you specified. A protocol can run on any port. Server and Client have to agree on which one.

On outgoing requests NAT or (Network Address Translation) within the router takes care of the re-routing of requests.

Every interface has a unique MAC address or (Media Access Control). It can be thought of as serial number. That's what makes every connection unique. The IP address is used for routing or where is this message supposed to go just like a telephone number. The telephone number is comprized of a country code, area code, exchange and a 4 digit "extension". That 4 digit extension. Telco wires are just that wires. Those wires need to be assigned to a particular SLI or Subscriber Line Interface that controls your phone.

Now your more confused, right?

More confused? I reckon so. How's about totally lost. You obviously know this stuff very well but you need to use baby talk to get me caught up with you. To answer one of your questions - I have DSL through Centurytel. Now -- when the poker site tells me that I already have an id using "this IP" -- what are they referring to? - can they see my "private IP (which as you said is 168.something or other)" or are they referring to the IP address provided by Centurytel? Thanks again for all yawlls help.

They can only see the Centurytel IP address.

I'm not sure if the MAC addresses (The one unique to your computer) can be seen outside of your subnet (192.168..? ) You might be able to try using wireless and wired. Each would present a different MAC address.

So I powered off my system (including the DSL modem) for about a half hour. When it came back up I went to "what's my ip?" and it shows a different IP now. So I figured I was home free. Tried to create a new account on the poker site. Now instead of grinching about the IP address it says something like "it appears there is already an account associated with the computer you are using". Now -- how in the world would they know that? Any suggestions on how to get around this stumbling block? Once again thanks in advance for any assistance.

This site has some good information -- Hope it helps you with your problem

What Is My IP Address? - How do I change my IP address? (http://whatismyipaddress.com/staticpages/index.php/how-do-I-change-my-ip-address)

You may want to pick a different site -- Some are better than others

how to change your ip address - Google Search (http://64.233.169.104/search?hl=en&q=how+to+change+your+ip+address&btnG=Google+Search)

I think they know your computer because of cookies -- You went to their site -- They gave you cookies

Please rate answer

The MAC address is a hardware encoded unique address embedded in each network device. It should not be changed even if you could.

In your first response you said you were doing nothing illegal or immoral. But if you are using a site that allows only one address and you are trying to make more than one in violation of their rules then that is unethical at best.