Lessons · Network switches · where a desk gets its address

The switch does not hand out addresses

A PC asks, and the request travels out of the VLAN its port is in to a server somewhere else. The switch's whole contribution is which VLAN that is.

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

So when nobody in one department has an address, the question is not what the server is doing. It is which VLAN those ports ended up in.

Read the Vlan column for the ports that are failing. A department failing together is a VLAN-shaped fault.

enable

In.

configure terminal

Configuring.

interface gi0/7

A desk in the department that is complaining.

switchport mode access

Access.

switchport access vlan 50

This is the line that decides where its request goes.

spanning-tree portfast

Without it the port spends half a minute deciding, and the PC has already given up.

end

Done.

show interfaces status

Gi0/7 sits in 50. If that should say 40, you have found it.

show vlan brief

And here is whether 50 is a VLAN anybody meant to create.

Let this port start forwarding immediately for the PC plugged into it.

spanning-tree

Blaming the DHCP server when a whole department fails at once. One department is usually one VLAN, and a VLAN is on the switch in front of you.

Practise where a desk gets its address on HoneA question on it now, a coding challenge where there is one, and it is remembered for review. Free, no email needed.