Port Forward down through Layer 3 Switch ???

[keithatwood]

I'm looking at implementing a cisco 3550 Layer 3 switch and would like to know if i can forward ports down to all of my differnt Subnet Servers/Pc's.

For example. See attached image.

10.0.3.5 is a mail server. 4.2.2.2 is our public IP.

I would like to forward TCP port 25 down to our Mail servers IP.

Does anyone know of a reason this will not work by using the cisco 3550? Currently we have a flat network (1 subnet) and port forwarding works fine.

Thanks!

[Reza Sharifi]

It should work fine. If you have EMI version of the IOS, you can do a full later-3 routing.  Since the network is not very big, I am assuming you are going to run static routes and SMI version of the software should work just fine for you.You need to create 4 SVIs on the 3550 (one for each subnet). The connection between the 3550 and the router can be a /30. /24 works fine too, but it doesn have to be.

Good Luck

Reza

[keithatwood]

Thanks very much!

Yes it is a small network and the 3550 is using SMI.

By SVI for each subnet, I'm assuming you mean add the following command:

Switch(config)#

interface Vlan2

Switch(config-if)#

ip address 10.0.2.1 255.255.255.0

Switch(config-if)#

no shutdown

And so on for Vlan 3,4,5 etc.

Then

Switch(config)#

ip routing

Correct ?

Thanks again!

[Reza Sharifi]

Yes, that is correct, one SVI for each subnet.  Don't forget to create the layer-2 vlan for each switch and add the proper interfaces to that vlan.

layer-3 vlan or SVI

Switch(config-if)#

ip address 10.0.2.1 255.255.255.0

Switch(config-if)#

no shutdown

Switch(config-if)#

ip address 10.0.3.1 255.255.255.0

Switch(config-if)#

no shutdown

Layer-2 vlan

vlan 2

name test2

vlan 3

name test3

and so on.

HTH

Reza