Lessons · Network switches · a config that does not fit the box
A configuration that does not fit the box
A port the chassis does not have is not a port, and the line naming it is refused -- whether the mismatch is the count or the interface names.
Hone is a place to practise programming. This is one of its lessons, written out in full and free to read without an account.
What it is for
The hostname and the uplink land either way, so a mismatch looks like a success. A 48-port config on a 24-port spare, or a Gigabit config on a FastEthernet box, both leave you with a switch that reads right and is not.
How to think about it
Read `show version` and `show inventory` on the replacement first. If the names differ, fix the file at a desk with a search and replace, before the copy.
Worked example
enableIn.
configure terminalThis box's ports are GigabitEthernet.
interface gi0/1Accepted.
exitOut.
interface fa0/1The same port number, the wrong family. Refused.
exitOut.
show interfaces statusWhat this chassis actually has, which is the list the file has to match.
Your turn
List what ports this chassis actually has.
show status
Console into a switch
The trap
Using a smaller spare and not telling anybody. It can be the right call at two in the morning; it cannot be invisible.