Private VLAN (PVLAN) on Cisco Catalyst Switch

Hello Shaimaa

I’m not completely sure what you want to achieve here with DHCPv6 and your isolated VLANs. In general, keep in mind that in order to get all hosts in all VLANs (primary, community, and isolated) to receive their IPv6 addresses via DHCPv6, the DHCP server must exist on the primary VLAN, and DHCP messages should enter the PVLANs on a promiscuous port. Otherwise, your hosts within an isolated VLAN will not be able to receive any DHCP messages.

In the event that you have multiple switches with trunks, you must first make sure that all the switches involved are PVLAN-aware. You must also ensure that you are configuring both switches correctly. Take a look at this NetworkLessons note on trunking Private VLANs for more info.

Can you give us some more information about your particular topology and the ultimate goal you want to achieve? That way we will be able to help you further.

I hope this has been helpful!


Hmm, I don’t this works in GNS3, I tried your exact config but no luck. I think this is one of those things that just work better with real hardware.

Hello Artur

After a short search, I have seen that some people have been successful in creating a GNS3 topology with private VLANs. I believe that the GNS3 forum is an excellent source for solutions to these types of problems. For example, take a look at this post that shows a topology with private VLANs on GNS3.

In the past private VLANs were not configurable on GNS3 but recent updates have allowed it. I suggest you do a little bit of research to further examine where the problem is in your topology.

Let us know how you get along!

I hope this has been helpful!


HI Laz,

I will give this set up a go and will let you know how I get along.


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