Hi everyone, I would like to share the internet connection from a non-Cisco home router with basic functionality between two VLANs, but I can’t. The two VLANs do not communicate with each other but should be able to navigate. I set up a multylayer cisco switch with a switchport access vlan 100 interface connected to the respective vlan to which I assign an ip address 192.168.100.1 / 24.
Then I assign a second interface to a second vlan, the vlan 200 and check 192.168.200.1 / 24
enable routing. I attach a home router interface to a switch port that I put as no switchport by assigning it as ip 192.168.0.254/24.
The home router has ip 192.168.0.1 / 24
I can’t share the internet connection. I forget something? help please.
Hello Samuel
Take a look at this diagram:
Now in order for this setup to work, you will require two things:
- A default route in the Cisco switch that points to 192.168.0.1.
- Two routes in the non Cisco router that tell the router where to route packets destined for the 192.16.200.0/24 and 192.168.100.0/24 networks.
My hunch is that you didn’t the the second. If that is the case, then packets destined for a destination on the Internet will reach that destination, but upon their return, the non Cisco router will be looking to send them to one of the two subnets/VLANs. If it has no information about how to reach those, then the packets will simply be dropped.
I hope this has been helpful!
Laz
Hello, thanks for the reply. So I assume that the .254 port of switch must be trunk, while the non-cisco router should have two routes set to the ip addresses of the respective vlan configured on the switch interfaces, right?
ok i succeeded by configuring the port to the non-Cisco router as no switchport. But in case you can’t put routes on the non-Cisco router, how can you do it? Do you have to insert another device?
Hello Samuel
This would be the case only if you could create a trunk or a series of subinterfaces (like router on a stick) on the non-cisco router, but this is not necessary. You can create a simple point to point layer 3 connection between the L3 switch and the non-cisco router, as all internal routing is taken care of by the switch.
If you can’t include routing commands in the non-Cisco router then you probably have a problem. You need to be able to have packets that come from the internet with a destination address of the host on VLAN 200, for example, to be routed to the appropriate subnet. Even if you put another device like a Cisco router between them, you still need the non-Cisco router to route packets to a network other than the one configured as directly connected to the device. Most commercial grade ADSL or Cable modems should have this basic capability. Otherwise, you can replace the non-cisco device with one that does have routing capabilities.
I hope this has been helpful!
Laz