If i want to configure the IPS for auto update , it asked for update server ip address, what is this ip address? is this auto update configuration needed for signature update, or it is for other updates?
You can't point at the Cisco site, you need to host your own internal server for this purpose. Personally, I do not use or recommend putting version upgrades in this directory (I believe it will try to apply them if you do). We use the CLI for installing version upgrades. We use autoupdate for installing signature updates.