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Cisco Catalyst 3550 VLAN Routing

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17 years 5 months ago #18348 by daisho
Hello,

Is there a way on the 3550 to remove and ignore all tagging.

Really I'm wanting to use this as a 48 port router so to speak. I've done it in the past but the devices that have plugged into it have always been "Dumb Switches" with no tagging so everything worked fine.

I'm in a situation now that I'm getting VLan mismatches since switches plugging into a port are manage and are tagged with VLan1.

Basically I'm making a VLan on the 3550 and assigning it to 1 port only and assigning the VLan a range of IP addresses. The solution would work perfect if I could ignore all VLan tagging and not tag anything since I want to use 100% layer 3 routing.

Thanks.
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17 years 5 months ago #18349 by havohej
Hi.

For the first answer: yes! you can turn the 48 switch port device into a 48 port router device, simply by disabling switcing feature in every port you want to turn into layer 3:

3550(config)# int range fast 0/1 - 48
3550(config-if)#no switchport

For the vlan mismatches don´t care it works! but you must set both ports in switchport access mode (the port used as uplink), never for trunking, or it will not work.

for example, if you have the following scenario:

3550(port1)
(port10)4507

port1 in the 3550 belongs to vlan 2, and is set to access only
port 10 in the 4507 belongs to vlan 7 and is set to access only.

at the console port of both switches it will appear as vlan mismatch detected at both ports, but it will work, sometimes, this is the only way to connect two switches, specially if you have ibm blade devices with cisco switches within the chassiss, damn switches you cant change lot of config.

also, as a security reason, if you have vtp enabled try setting one of the switches as transparent, mean the new one connected to the border switch of your vtp domain.
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17 years 5 months ago #18362 by Smurf


3550(config)# int range fast 0/1 - 48
3550(config-if)#no switchport


Didn't know you could do that. I'll use that range command :)

Wayne Murphy
Firewall.cx Team Member
www.firewall.cx

Now working for a Security Company called Sec-1 Ltd in the UK, for any
Penetration Testing work visit www.sec-1.com or PM me for details.
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