Switchport trunk allowed vlan all

[lruberintwari]

Hi,

i have attached my secenario below and i would that PC in vlan 1 send and receive from vlan 2 and 3 but don't want thant vlan 2 communicate with vlan 3. I used switchport trunk allowed vlan all on the switchport that is used to connect to the Pc of vlan1 but i don't have the expected result. Please any help will be welcome

[charitha1013]

I will try this approach and let you know how it goes. Thanks a lot.

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[charitha1013]

It's too tedious; is it worth the effort to identify and allow certain vlans vs allowing all to the existing network?

Is there any other easy way looking at the show commands, configs etc and identify the vlans ?

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[JohnTylerPearce]

Charitha1013,

Step 1) 'show vlan brief' (This will show you what ports have been assigned to what vlans, as well as all vlans created on the switch)

Step 2) 'switchport trunk allowed vlan add a.b.c.d.e.f (etc etc)'

Step 3) You can control broadcasts this way. By default a trunk belongs to all vlans, so if you only have vlans 10 through 30 on a switch, the trunk port on that switch will receive all broadcasts for all other active vlans.

[charitha1013]

Thank you for the reply. It was very helpful.

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[JohnTylerPearce]

Charitha1013,

Glad I could help.