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New Member

Problem between 2 VLAN


I use CISCO ESW 520 since 2year and i have a strange problem with new VLAN.

I add a new VLAN for a new activity (VLAN 9), in this VLAN i have a DCPH and a system that can erase operating system on boot on network.

But this VLAN 9 communicate with the VLAN 4.

It's the first time that I see that, because they are no problem with the other VLAN, and the only RJ45 with the VLAN 9 untagged are not plug.

Have you ever seen that?

I continue the investigation but if you have idea.


  • Small Business Switches

Problem between 2 VLAN

Hi Thibaud, let me try to clarify.

You created a VLAN 9. There is only 1 port  a member of VLAN 9 which connecting to a DHCP/server. Does this VLAN 9 exist anywhere else?

The ports connecting to your router / other switches, are these tagging VLAN 9? This would be expected to happen automatically because of the smart port macros.

Please rate helpful posts

-Tom Please mark answered for helpful posts
New Member

Problem between 2 VLAN

Ok I just change Trunk Vlan port to Access Port VLAN and the problem is solved.

Thanks for your help.