how do you read the line or port numberinig on a cisco 2851. if it's module number, wic slot number and port number. For example if it's gigabit 0/1, what is the 0 and what is the one? or when there's serial 0/0/1, what is the first 0, second 0 and 1?
Interface IP-Address OK? Method Status Prot
GigabitEthernet0/0 192.168.217.1 YES NVRAM up up
GigabitEthernet0/1 unassigned YES NVRAM administratively down down
Serial0/0/0 unassigned YES NVRAM down down
The command reference is the best way to review these kinds of parameters:
Generally, the command syntax is slot/port or slot/port-adapter/port.