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How to create a Vlan allowing only NBX100 traffic Through

Posted on 2007-08-01
Medium Priority
Last Modified: 2010-05-19
I have a 3 Com NBX 100  Phone system integrated into our network (building A). The system is connected to a 3com 2226 pwr plus switch. I have another building (building B) on a different subnet and that network has a 3 Com 2226 Plus switch. The two buildings are connected through fiber, and plugged into ports on the 3com switches at both buildings. Because there are no Vlans setup between the buildings, traffic from building A is in B. I want to create a vlan between to the two buildings only allowing NBX traffic through. I am not familiar with 3com switches so detailed information on creating the Vlan would be great.
Question by:raygraham
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Expert Comment

by:Will Szymkowski
ID: 19614192
Here is a PDF document that explains how to setup a vlan using your 3com switch. I believe the Creating Vlans starts on page 35.


Hope this helps
LVL 27

Accepted Solution

pseudocyber earned 375 total points
ID: 19615894
Off hand, I don't think you can do it.  If I understand you right, you're wanting to filter traffic based on the type of traffic - which is at least layer 4 the Transport layer - where TCP/UDP live.  There are layer 4 and up switches, but your 3com 2226's don't appear to be layer 4 switches (I just glanced over the spec sheets).

You could put firewalls on one side of the link to seperate it from the two buildings.

I don't know your switches, so I could be wrong on this ....

Author Comment

ID: 19615946
Thanks for the Vlan document. I guess real question would be, how do I keep subnet a and b seperated, because the phone system  originates on subnet A (building A). From what I understand about this phone system it does not use IP addresses. It is mac address based.  I need a way to allow only the phone protocol through and not allow anything else through.
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LVL 27

Expert Comment

ID: 19615987
By design, vlans seperate layer 2 networks.  A device on A should NOT be able to communicate with a device on B.  That's the whole idea about vlans.

You could do MAC based Access Control Lists on Cisco gear.  It would be a PITA, but you could do it.

Author Comment

ID: 19616032
I think pseudocyber is right. I monitored the traffic on the Subnet A with ethereal and it uses protocol 0x8868, And under "info" ethreal says ethernet II.  If I have to use a firewall between the segments, I need to find one that supports this protocol. Anyone know?

Author Comment

ID: 19645324
tried using a managed switch and using acl's to allow the phone though, but the 3com 2226's seem to be proprietary. So were are having the phones changed to IP based which I can deal with.

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