topic Re: VLAN Routing Problem in Switches, Hubs, and Modems

VLAN Routing Problem

Rajiv Dodderi — Sat, 06 Jan 2007 08:47:05 GMT

I have 2650 series switches and in a mess trying to configure VLAN routing.

Scenario

VLAN1 - Infra VLAN
VLAN2 - Project1
VLAN3 - HR
VLAN4 - Rest of Organization

VLAN1 should be able to talk to VLAN2,3 & 4 and vice versa since the infra VLAN will have the router, Domain controllers etc

VLAN2 ,3 and 4 should not be able to talk to each other.

I have been trying this on a single physical switch by segreggating the ports and unable to successfully route between the VLANs.

Is this scenario possible without having to buy a router?

Note* I have a single physical network.

Eventually I will have 5 2650 48 port switches catering to 240 LAN points altogether.

Re: VLAN Routing Problem

Mohieddin Kharnoub — Sat, 06 Jan 2007 23:47:01 GMT

Hi

The 2650 can easily route between its Vlans without any problems.

Usually, for a Vlan has internet connectivity (Vlan1 i assume in your case), a default route command should be entered on the 2650 switch global configuration, and on the router side, you should add 3 Static routes to your Vlan2,3 and 4 (Route Back).
Example, if you have 4 Vlans with these IP addresses,
Vlan1: 10.1.1.1
Vlan2: 10.1.2.1
Vlan3: 10.1.3.1
Vlan4: 10.1.4.1

In your case, Vlan1 has the router and Servers ...., so if this router for internet or WAN connectivity, add the following static routes:

ip route 10.1.2.0 255.255.255.0 10.1.1.1
ip route 10.1.3.0 255.255.255.0 10.1.1.1
ip route 10.1.4.0 255.255.255.0 10.1.1.1

or you can summarize:
ip route 10.1.0.0 255.255.0.0 10.1.1.1

This will guarantee your route back, but, say you disconnected this router from the 2650, and you want simple to route between a station on Vlan4 and another on Vlan3, then you should be able to do that when you enable routing on the 2650 switch.

Good Luck !!!

Re: VLAN Routing Problem

Matt Hobbs — Mon, 08 Jan 2007 00:26:19 GMT

With the 2600 Series you will not be able to achieve this goal: "VLAN2 ,3 and 4 should not be able to talk to each other."

Usually you would do this through ACL's which the 2600 does not support, or source-port filtering - which does not work on the 2600 when using routing.

I would recommend you look into something like the 5300xl as your core switch instead.

Re: VLAN Routing Problem

Rajiv Dodderi — Mon, 08 Jan 2007 03:24:43 GMT

Thanks for letting me know.Can I achieve the same scenarion by placing a firewall between the VLAN ? or another switch which can act as a router and also have ACL ?

we have already purchased 5 of these switches and re investing in new switches may not go well with the execs.

What other alternatives do I have ?

Thanks in Advance.

Re: VLAN Routing Problem

Rajiv Dodderi — Sat, 20 Jan 2007 06:11:23 GMT

Answer Received to my queries