| 11 | * Switch as DHCP client |
| 12 | |
| 13 | == Undoing Configurations == |
| 14 | Most of the time, just adding the command `no` to the beginning of what you see when you do the command `show configuration` will suffice for undoing configurations, but occasionally you get something like this: |
| 15 | {{{ |
| 16 | (config)# no vlan 4 |
| 17 | vlan : Can't delete this configuration referred by other configuration. |
| 18 | }}} |
| 19 | This happens when the configs for an interface that you are trying to delete are associated with something else; you need to undo any configurations associated with an interface before you can delete it. In this particular case, VLAN 4 is associated with port 0/27, and you need to undo the configurations to port 0/27 that have to do with vlan 4 before you can get rid of it. |
| 20 | {{{ |
| 21 | !(config)# int gi 0/27 |
| 22 | !(config-if)# sh |
| 23 | interface gigabitethernet 0/27 |
| 24 | switchport mode access |
| 25 | switchport access vlan 4 |
| 26 | ! |
| 27 | !(config-if)# no sw acc vlan 4 |
| 28 | !(config-if)# exit |
| 29 | !(config)# no vlan 4 |
| 30 | !(config)# |
| 31 | }}} |
25 | | 3. Specify which VLANs are allowed on the trunk. This includes all VLANs that converge to this trunk, as well as the native VLAN for this trunk. Since this port had already been assigned other allowed VLANs, instead of using command `switchport trunk allowed vlan 1,3,27,28` you can just add VLAN 1 by using the `vlan add <vlan ID>` context: |
| 46 | 3. Specify which VLANs are allowed on the trunk. This includes all VLANs that converge to this trunk, as well as the native VLAN for this trunk. If the port is already made to allow other VLANs, instead of using command `switchport trunk allowed vlan 1,3,27,28` you can just add VLAN 1 by using the `vlan add <vlan ID>` context: |