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Re: VLAN Question,

New Member

VLAN Question,

I have a question concerning VLAN's and routing across these. I believe that I am trying to do something which can not be done, so here goes.

Our current network is setup with 3 VLAN's, ID 1=default, 10 and 20. Our Internet router is 1/4 mile away and we connect to this via fiber with two hops in between. The switches in place are Pro Curve 2626. So the connection is Internet router >> Switch >> Fiber >> Switch >> Fiber >> Switch in office. All switches are set to "see" traffic from the 3 vlans in place, and our network is using the following address internally > We are currently starting to update our core servers and I would like to do a parallel install with our new network servers, switch, firewall.
Our current firewall sits at the end of the fiber connection and has an external address assigned to this. I have configured a separate firewall with a different external ip address and plugged this also into the same switch in our office and plugged this into a port configured with a new vlan id 30, which is set on all the fiber ports on the switches back to our internet router. Since the fiber ports on all switches are trunked to see all the vlan traffic and pass it accordingly, when I assign an ip address on the new network of 192.168.20.x, I can still ping the 192.168.20.x addresses on the old network. The reason for this is because ( I am assuming )that the fiber ports are set as "Tagged" in all vlans, and I will either need to use a different IP address structure for my new network internally, like (, or have a totally different connection to the internet.
When I have setup the new vlan id 30, and "Tagged" the fiber ports accordingly so traffic on this vlan does get out to the internet, I have also set the other ports to "Forbid" access to this vlan, however I think since the fiber port is still tagged into all vlans, this is what is causing my problems...

Trusted Contributor

Re: VLAN Question,

Can you please post your configuration here.
And maybe say in other words that you try to achieve.

About "Forbid" status of port: this status is for GVRP protocol, not for static VLAN assignment.
Honored Contributor

Re: VLAN Question,

>>> this is what is causing my problems <<<
your'e not clear about what problem you have...

If I read your story correct, you just have multiple VLAN's across multiple switches.

A V(irtual)LAN behaves same as a (physical) LAN.
The switches just forward data to ports within the same vlan.
They add a "tag" to the packet on the link between switches so the receiving switch knows what vlan this packet belongs to, and remove the tag again if sent to a host (untagged port)

Look at it as two separate networks network "vlan20" and a network "vlan30".
that connects port in vlan30 in your office to another port in vlan30 in the location where the internet router is.

- The internet router forwards either to firewall-1 or firewall-2 depending on the public addresses used.
- data from firewall-2 is forwarded on vlan30 to your office
=> I see no problem there

!!! I asume the switches do not route between vlan's, so data in vlan30 is totally separated from data in vlan10 and vlan20 .
==>> You can even use same adresses in vlan30 and vlan20. the switches won't care about this.