How the NNTP psting host gets added to the post is dependent on the software that injects the posting into the newsfeed. This software is probably at your ISP, which means they get to set the policy of how it is set. If you want to truly change it, you need to either find an ISP specific solution, or use a different method of getting your news into the newsfeed. Whether there exists an ISP specific solution, depends on your ISP. For example, my ISP does not associate my postings with my computer--in fact, it doesn't even know the name, IP, or MAC address of my computer.
Now, when I talk about my ISP (The World), I'm not talking about my cable provider, which is what connects my home to the (and does know my computers IP and MAC address) internet, nor the way my work setup is connected to the internet either. I am talking about a specifc company that provides exactly the service of getting mail and news from the internet and posting news onto the internet--thus I should probably really call it my mail/news service provider. I do that for exactly the opposite reason of what you are asking for, so that I have a well know address that people can reach me at that doesn't change over the years. However, one could use it to get what you want privacy.
I have also used "free email" addresses to get something closer to the anonymity you are seeking. Those are relatively effective. You can use those to create postings, if you learn how, and if so, you are likely to be mostly anonymous, and your posting won't be easily (i.e. by your kids) tracked back to you, unless they hire a professional.
If they hire a professional to track down your information, you aren't likely to be able to get the privacy you desire. (So, for instance, if you are cheating on your husband, he will find that information out, even if you try to keep it private. Noreover, he will find out not via tracking your internet posting IPs. As they say, been there, done that.) You should also assume that most "kooks" are capable of doing what professionals do.
In other words, a motivated person can break your privacy shield. An unmotivated person will probably never know (nor care that) you are trying to keep something private. There are simple things that can assist your privacy. Using a free email service to create a "disposable" email address is one of them. Trying to hide your home computers posting address, is not one of them. If you want to disassociate from some posting, DON'T DO IT FROM YOUR HOME COMPUTER.
If you are ashamed of your previous postings, sorry it is too late. You are better off figuring out how to deal with your choices of actions, rather than trying to hide from them.
You keep trying the attention of this thread on how to hide your IP/NNTP posting host. You may or may not be able to do that via an ISP specific solution. Most DSL modems and routers aren't designed to make it easy for you to change their IP address by forcing them to renew it. Keeping the IP address constant is an efficiency issue. It is generally more useful to keep the address constant, than it is to change it. However, with a server that has more potential modems connected than addresses, it is useful to "release" addresses of modems that aren't connected, because the assumption is that most modems are not connected, because they can't all be connected, given that there aren't enough addresses. Therefore, your ISP may recycle IP addresses, to serve a large community with fewer resources. Still, that is for their benefit not yours, and how often they recycle addresses may (or may not) be something you can influence. You can play with your modem settings (and it is more likely the modem settings if you have a separate modem and router--note my modem has NO user configurable settings). However, even if you change them, you may have to turn your modem off to get it to release the IP address. Moorever, your IP may reassign the same IP address when your modem is turned back on, if that is convenient to them, and quite likely will give you the same address if your modem is off for a sufficiently short period of time.
Note, if your modem has a MAC address, I defintely recommend NOT trying to change that. It is quite likely that your ISP keeps a list of the valid MAC addresses for the modems connected to its service, and only allows those MAC addresses to connect. By the way, many ISPs use the MAC address of the first "computer" (or router) after the modem as the address they keep in their database (at least that's what my last 3 cable providers have done). That's one of the reasons many home routers allow one to override the hardwired MAC address, so that one can make it look like the computer the network was originally "provisioned" for. Thus, I wouldn't change the routers MAC address either.
However, the key point of all of this, is that if you want your postings/email to come from a different address, then do that. Use a different way of injecting your eamil/news into the web rather than simply posting from your home. However, don't try to achieve that by fiddling with your local computers IP address. Wrong solution to the problem.
Hope this helps,
-Chris
***************************************************************************** Chris Clark Internet : snipped-for-privacy@world.std.com Compiler Resources, Inc. Web Site :------------------------------------------------------------------------------