ISATAP can be very useful if you need to manage out from a machine with an IPv4 address to a machine with an IPv6 address. This is commonly used where DirectAccess has been deployed as all DA clients will be using IPv6. Being able to RDP to them or use the SCCM Remote Control feature from a machine inside your network is very helpful for the IT support staff – it’s as if the user was just working from their desk like usual!
One time I was configuring an ISATAP interface on a server and I got the follow error in the event log:
Unable to update the IP address on ISATAP.yourdomain.com. Update type: 1. Error Code: 0x490
I scratched my head over this for quite a while – setting up an ISATAP interface should be easy! After a while I remembered that there was a history of disabling the IPv6 components on servers via GPO. It turns out that even though the GPO had been removed, the setting to disable IPv6 had been tattooed on the servers it had once been applied to.
To check this I had a look in the following location in the registry:
The value was set to
0xFFFFFFFF (it may instead be set to
0xFF). This disables enough of the IPv6 components to prevent an ISATAP interface from being able to be created.