Manual Configuration as ISATAP Client

Since Service Pack 1 ISATAP, like all IPv6 functionality, is configured using the “netsh” command in the command shell. Only the IPv4 address of an ISATAP server is needed to configure a Windows XP host as an ISATAP client. (Of course it is required that IPv6 be installed on the host before using “ipv6 install”). The full command to set up ISATAP after that is:

C:\>netsh interface ipv6 isatap set router \
                                                                        <IPv4 address of ISATAP router>

This is it. With the command “ipconfig /all” one can verify that the host has indeed received router advertisements from the server and configured its interface accordingly with an IPv6 ISATAP address. Using the command “tracert” or typing

C:\>netsh interface ipv6 show route

further shows, that the default route is now also configured for the ISATAP interface (number 4), even though 6to4 probably still also is configured.

Automatic Configuration as ISATAP Client

When the IPv6 protocol is started (e.g. at boot or installation) and realizes that there is no native IPv6 connectivity on the link, it tries to resolve the hostname “ISATAP” (on Windows XP without SP1 “_ISATAP”). If this hostname resolves into an IPv4 address the host will configure itself as an ISATAP client for this server and set the default route accordingly. Please note that the host will also
configure 6to4 but just as a backup to the ISATAP connection or to communicate with other 6to4
sites.