Once you have a new IPv6 address, you'll also need a router or firewall that supports IPv6. Such products are still hard to find, especially in less-expensive, small-business-oriented versions. Cisco and other top-tier products have IPv6 support--although even there, often the only way to know which products support it is to read the manuals.

Getting IPv6 to work can be tricky, and support is typically difficult to come by. You need to verify that your ISP can support your switchover and your specific router before you even try to upgrade; ask your provider which router is recommended. (D-Link, for one, has a reputation for IPv6 compatibility.) You should also plan on having both an IPv4 address and an IPv6 address for a while, and you should make sure that your ISP supports running both protocols simultaneously.

If you have an IPv6 address, and your router or firewall has IPv6 support, you may not need anything more. The router should be able to translate between your internal IPv4 network and the Internet, and unless or until you need to connect more systems than just an e-mail or Web server directly to the Internet, you might not have to make any more changes.

Eventually--when all your PCs are running Windows 7 or later and your servers are running Windows Server 2008 R2 or later, and when all the rest of your network hardware is less than two years old--you may want to consider moving to a completely IPv6 network.