I'll try to be "short." I've successfully enabled http server option on my Cisco 870, now I need to reach it and use the web based configuration. I haven't found how to assign an IP to the router itself. How can I do this?
You can assign an IP address either to a physical (Ethernet) interface or to a VLAN including one or more of them; the default configuration has all interfaces sitting on VLAN 1, so the easiest approach is assigning an IP address to it.
That would be: