I have a DSL line coming into a router/modem, from which there are seven outputs with their own IPs. Five are connected (wired) to their desktops. What should I use to get the sixth connection and share it wirelessly to three other computers: an access point or a router? I want to use the sixth IP and share it between three other computers. Is this possible, and if so, how?
In order to share your DSL line with three more computers, it will be necessary to add another router to the sixth port. This router needs to have wireless LAN (WLAN) capability. Make sure the WLAN router you buy is Wi-Fi compliant. When it comes to WLANs, you have a choice. IEEE 802.11 revision b and g WLANs operate in the 2.4 GHz radio band, are the most common and the best bang for the buck. They are also the most compatible with public hot spots, such as the ones in Starbucks, American Airlines Admiral and United Red Carpet Clubs -- an important consideration if any of the three new computers are laptops that you may plan to use outside your home or office area. One caveat: if you have a cordless phone that operates at 2.4 GHz in your home or office it will interfere (often severely) with your WLAN performance if you use and 802.11b/g WLAN. That will either force you to go out and get a new cordless phone (get one that operates at 5.7 GHz), or you will have to get a WLAN router that supports IEEE 802.11a, or a/b/g. You would be well advised to look at products from Linksys, SMC and D-Link. The same advice on WLAN choices/guidelines apply to the WLAN that is inside the computers you place on the network.
It is also going to be necessary to configure the starting address block for the computers connected to the new router. This is necessary so that the client computers that are added to the second router do not wind up with the same IP addresses of the computers on the router you already have installed. Because I don't know if you have configure your existing router with fixed IP addresses for each computer connection it or you are using DHCP, it is not possible for me to give you exact instructions on IP address configuration.