WOT: need computer help...., need to assign an IP address to a particular computer.... Options

[scottb]

on my network.

i have a linksys BEFSR41 and have 2 IP addresses through comcast (at least that is what they tell me).

i need to do the following:

find out my IP addresses

assign one of these addresses to my wifes work computer, and let the rest of the house use the other.


i have messed around within the router but as i don't know my ip addresses. i do an ipconfig and only get one ip address.

so any suggestions oh wise ones? my wife an i both work for the same company and the security system is such that only one log in per ip address is allowed (hence the need for 2).

hope this is clear enough....

thanks,

scott

[Richard Casto]

Scott,

Sorry you are still having issues. If it was me, the top things I would try to work on would be the following...

1. Make sure I can build a working (secure remote connection) setup with just one computer so you will know what does work. You may have already done this.

2. If #1 includes the router in the path, then all the better. Sometimes a router setup to also do NAT may cause problems with the type of things you are trying to do. If #1 does not include the router, then I would try to build a working setup (again just the one connection) that does work with a router in the loop. You may want to look at a setting on your router. On my Linksys this is known as the VPN passthrough. You may want to see if you have a setting called "IPSec passthrough" and make sure it is turned on.

3. Once you have the above working configurations, the you can move onto trying to get two live internet connections. Again assuming you really need two public IP addresses, then I would focus on just seeing if you can get two different IP addresses from your ISP. In your diagram above it would be the two routers that would be getting the IPs. On my Linksys I can view a status page that tells me what IP addresses that the ISP gave the router. It probably also provides the default gateway and DNS (two or more is OK). Both routers should get the same info except for the actual IP address. At this point just make sure you can both address the internet at the same time from two PCs that are using two different routers. Just web surf type of thing.

4. If you get this far, you should be able (cross fingers) to combine the results of #2 and #3 to make two working setups (one for you and one for your wife).

Regarding NAT. Here is a good link...

http://en.wikipedia.org/wiki/Network_address_translation

If that Wiki page is too complicated I will give a quick explanation. Basically as you can tell ISPs will give you one free public IP address and then charge you for more. But you may have multiple computers in your house. And each of those need an IP address to communicate to the rest of the world. So what do you do?

So lets say your ISP gives your router the address of 24.40.136.100. What NAT does is use a special "range" of IP addresses that everyone agrees will never be used as public IPs. Your router can be setup to give out those addresses to your PCs at home as needed (via something called DHCP). A commonly used range is 192.168.1.XXX. So if your PC boots up and asks for and IP address, your router catches that request and gives out the first unused number (lets say 192.168.1.1). Another PC then boots up and it asks for an IP and it gets the next number (lets say 192.168.1.2). When you goto a web site, the router acts as a middle man and the remote website actually things it is talking to 24.40.136.100 even if both PCs are accessing the same site. The site sees just the same IP address. There is other info buried in the what is going back and forth that allows the router to redirrect the info the the proper PC in your network.

It is very likely that you are using NAT (which is not a bad thing) and if you and your wife are using two different routers then you both may end up with the same IP address. In my example above I used 192.168.1.1. There is probably millions of PCs on the planet that are using addresses in that same range. But because of NAT their public IP is something different and multiple PCs are sharing singular public IPs. The entire thing started years ago when they were experiencing a shortage of public IPs. If you and your wife need different public IPs, then what is important is that your "routers" have different IPs. And that is what you should be able to see via the status info somewhere.