# Interface R1 # sh run int Fa1/0 interface FastEthernet 1/0 IP address 172. 16. 12. 1 255. 255. 0 duplex automatic speed automatically ends R1 # sh ipv6 int bri FastEthernet 1/0 [up/Up] FastEthernet 1/1 [administrative down/down] not allocated R1 (config) # intfa1/0r1 (config-if) # IPv6 addr? WORD common prefix name X:X:X:X:X IPv6 link local address X:X:X:X:X/《0-128》 IPv6 prefix automatic configuration using automatic configuration to obtain address # failed to configure local link address.
