TRUNK

[jonk34567]

#int fa 0/0

# switchport allowed vlan 10,20,30

#switchport allowed vlan  40,50,60

so here how many vlan will be allowed 3 ( 40,50,60 ) or 6 (all )

[Jon Marshall · Accepted solution]

Depends on what you mean. 

The actual command is "switchport trunk allowed vlan <vlans>" and it is done under interface configuration mode. 

So if you mean those are commands to be typed in one after the other then it would be just be vlans 40, 50 and 60 because the second command will overwrite the first one.

If you wanted all vlans then your second command should be - 

"switchport trunk allowed vlan add 40, 50, 60"

Jon

[Joseph W. Doherty]

Touche!

[Joseph W. Doherty]

If I remember correctly, that command is additive, so I would say six.

[burleyman]

I ran this on a 3750 switch and he is what the results were.

3750-24#config t
3750-24(config)#int fa1/0/24

3750-24(config-if)#switchport trunk allowed vlan 10,20,30
3750-24(config-if)#switchport trunk allowed vlan 40,50,60

The results show only the last command stays.

3750-24#show interface switchport | be Fa1/0/24

Name: Fa1/0/24
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Administrative Native VLAN tagging: enabled
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk associations: none
Administrative private-vlan trunk mappings: none
Operational private-vlan: none
Trunking VLANs Enabled: 40,50,60
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL

Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none

Mike