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SG300-10 Layer3 - HELP! Change default IPv4 route + Stacking 2x SG300-10 Switches

I have two issues.

First, my SG300-10's default IPv4 route keeps defaulting to the lowest numbered subnet I put on the switch. I'm using 10.xx.xx.0/24 subnets. My VLAN1 is on subnet and VLAN11 is my WiFi guest access with subnet. The SG300-10 keeps making the default route with a "next hop" of This is a problem as VLAN11 is locked down like crazy and cannot access anything other than restricted and filtered internet. 

How do I change the setting so that the default route and owner are subnet


Second is adding a second switch to the network. Switch 1 will have ports 7&8 in a non-LACP LAG which will plug into Switch #2's ports 9&10. Do I set that switch up the same as the top level one or do I need it to have switch #1 as its "next hop"?

2 Replies 2

Aleksandra Dargiel
Cisco Employee
Cisco Employee

Hi Network1Operations,

First of all:

1. your SG300 switch is in layer 2 or layer 3 mode?

2. your IP address is statically or dynamically assigned? 

It looks to me you have received IP from DHCP server and this is where the default gateway is coming from...


1. how many routing devices do you plan to have on your network? if only one, there is no need for next hope settings. 

I hope it is good start for analysis.



I have a SG300-10 and a SG300-28P that I am trying to implement currently. (I have many SG300 switches so I can use different models if that is better.) I have the SG300-10 in L3 mode and I am trying to use it as somewhat of a core switch. I would like to add the SG300-28 below it. The SG300-28P is currently also in L3 mode. 

I have two WANs a firewall and my LAN/L3 network. My firewall is plugged into ports 9&10 of the SG300-10 and my WANs are plugged into ports 7&8. That leaves 1-6. My plan was to set up a non-LACP LAGG on ports 5&6 going to my main file server (bare-metal 125TB FreeNAS server) and set up ports 3&4 as LACP link between the SG300-10 and SG300-28P, or, possibly ports 2-4 as an LACP LAGG going between the two, still doing the math on connections and data transfers. 

From there, the SG300-28P would handle most of the heavy lifting. Not sure if it should be in L2 or L3 mode. Attached to the SG300-28P will be a few L2 switches, three ESXi hosts, WAP's, a second ~100+TB file server and a a few other L2 switches with phones and other audio devices. My primary FQDN AD server is hosted on one of the ESXi hosts so the routing devices/points are all over the place with firewall handling some and AD server handling the rest. 

I was trying to use the firewall's DHCP server for the addresses on the network but when the switch pulls a dynamic IP it seems that the firmware assigns "next hop" as the lowest numbered 10-dot subnet which is an issue for my situation. 


To be clear, I am trying to use the L3 switches so that I can avoid bottlenecks by pushing all network traffic through my router/firewall. My firewall only has 2x 1GbE interfaces connected as LACP to SG300-10 however I have over 300TB combined on the network and 3x ESXi hosts with over 50 VMs. Some clients/machines easily saturate the link between the switch and the firewall creating a major bottleneck previously. I am trying to avoid the network traffic having to go back up through the firewall and stay at the L3 switch, as long as traffic is within the same subnet. 

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