It depends on what you mean by "using". Most routers have the ability to prevent groups of users from accessing Internet-based programs and services. This feature goes by different names including, Port Filtering, Access Control, Outbound Firewall Access rules, and others. But they all allow you to block Internet access to things like Web browsing, file transfers, mail, newsgroups, etc.

This is done by blocking the port used by the application for particular IP addresses that you program. The Port Filtering feature, however, does not prevent users from connecting to each other through the router's switch for File and Print sharing services. All it does is block access to the Internet-based services that you specify.

Many wireless Access Points have a feature called Mac Address Filtering or Association Control. This basic form of this feature allows you to enter a list of MAC addresses for clients that will be blocked from accessing the wired LAN that the AP is connected to. Sometimes you get two lists, one for blocked users and one for allowed users. Note that this feature controls LAN access, leaving decisions about Internet access up to whatever is providing your LAN's connection to the Internet, i.e. your router.

So what happens on a Wireless Router, which is conceptually the combination of a router and wireless Access Point? Well, it all depends on how the router is designed. As we described above, the router's Port Filtering feature is primarily focused on Internet access control and probably doesn't prevent wireless clients from accessing your wired LAN.

So what's a wireless router buyer to do? The best advice we have is to look for a feature in the wireless section of the router's administration screens that lets you enter MAC addresses of wanted or unwanted clients. Chances are, you'll have found the ability to control wireless client AP association. If your wireless router only provides IP address-based Port Filters or Access controls located in the router's firewall or other non-wireless admin sections, your product probably does not have wireless Association controls, and will let wireless clients access wired LAN clients unless you enable WEP encryption to block wireless client access.