SG350x-48 vlans and layer 3 setup

[edisoninfo]

I have used the SG300 numerous times in layer 3 mode to route between vlans with no problem. This SG350X however is totally new and I can not make it work. Each port can be set individually to layer 2 or 3 instead of the entire switch.  Any port set to layer 3 can not communicate to anything! With the ports in layer 2 mode (the default) I can get all of my vlans to communicate to the internet via my firewall/router. (Yes I have return routes in the router back to the SG350X) . I can NOT get inter-vlan routing to work at all. The whole point of purchasing a switch with layer 3 in it is to let it do the routing. I do not want my internet router doing the entire network routing.

I can not find ANY documentation or examples of how to use the layer 3 mode on a port. Help????

[Georg Pauwen]

Hello,

reading through the admin guide (attached) it sounds like the SG350X cannot do inter Vlan routing, and you need an external router:

VLAN Roles
VLANs function at Layer 2. All VLAN traffic (Unicast/Broadcast/Multicast) remains within
its VLAN. Devices attached to different VLANs do not have direct connectivity to each other
over the Ethernet MAC layer. Devices from different VLANs can communicate with each
other only through Layer 3 routers. An IP router, for example, is required to route IP traffic
between VLANs if each VLAN represents an IP subnet.
The IP router might be a traditional router, where each of its interfaces connects to only one
VLAN. Traffic to and from a traditional IP router must be VLAN untagged. The IP router can
be a VLAN-aware router, where each of its interfaces can connect to one or more VLANs.
Traffic to and from a VLAN-aware IP router can be VLAN tagged or untagged.

https://www.cisco.com/c/dam/en/us/td/docs/switches/lan/csbms/350xseries/2_4/admin_guide/english/AG_Tesla_350_550.pdf

[edisoninfo]

I sure hope that is not true. It would mean they took away functionality between the 300 and the 350X and I purchased a piece of junk. My 300 was hit by lightning and in replacing it I figured I would stick with the latest and greatest model. It is starting to appear I made a mistake and should have purchased the HP. 

That said, there are layer 2 / layer 3 settings on each port. I would hope there is a way to do what the older model did, I just need to figure it out.  Thank you for the reply.

[Georg Pauwen]

Hello,

actually I am not really sure why they would put this in the admin guide, as it would be reallly weird for the SG350 to all of a sudden become just a dumb layer 2 switch.

Check the document below:

Layer 3 InterVLAN Routing Configuration on 300 Series Managed Switch

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-small-business-300-series-managed-switches/smb2193-layer-3-intervlan-routing-configuration-on-300-series-manage.html

[cyberconsultants]

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@Georg Pauwen wrote:

reading through the admin guide (attached) it sounds like the SG350X cannot do inter Vlan routing, and you need an external router:

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It's borderline irresponsible to post this level of misinformation. It should be obvious that this is not true.

[Yoxio]

I also don't understand how the L2/L3 port config work. However, with SG350X-24 switch, after creating VLANs, assigning port to VLANs, enabling IPv4 Routing and assigning VLANs interface IP then I can ping PC on the other VLAN. I assume "IPv4 Routing" is a layer 3 function.

For internet access, I also get it done by configuring IPv4 Static Routes on both the switch and the internet router.

[cyberconsultants]

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@Yoxio wrote:

For internet access, I also get it done by configuring IPv4 Static Routes on both the switch and the internet router.

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This is the answer to OP.

[cyberconsultants]

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@edisoninfo wrote:

I can not find ANY documentation or examples of how to use the layer 3 mode on a port. Help????

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The only port that should be configured specifically as an L3 port is your WAN/external/edge router link. Appropriate static routes need to be configured between the two routers.

The switch performs inter-VLAN routing so long as the "IPv4 Routing" checkbox is ticked in the GUI (or by executing the command ip routing). ACLs need to be configured to control routing between VLANs as the default inter-VLAN routing mode is completely 'open.'