Lessons · Network switches · what you leave for the next person
The note is the only history a switch has
A configuration has no comments to leave a reason in. Everything about why tonight went the way it did lives in a note or it lives nowhere.
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
A runbook written after your first swap is worth more than one written after your tenth, because by then the things that stopped you have become invisible.
How to think about it
Collect the facts while you are still standing there -- they are four commands -- and write the short version somewhere the next person actually looks.
Worked example
enableIn.
show inventoryWhich box went in. Nobody can reconstruct this later.
show version | include serialThe number the warranty and the asset register both use.
show vlan briefWhich VLAN names you had to retype, because the backup did not carry them.
show interfaces statusWhich ports came back, and which one you had to think about.
show running-config | include hostnameAnd what the box calls itself now.
Your turn
Read the physical parts list off the switch.
inventory
Console into a switch
The trap
Putting the note in the login banner. Everybody who logs in reads that, including people who should not be reading your change history.