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Default gateway issue

Level 1
Level 1

Running into an issue with placing a layer two switch into production and could use some assistance. So in our environment we have a firewall that handles all of the DCHP and routing to the internet, our switch just acts as a layer 2 device (Catalyst 9300). For some reason when placing the switch into our environment I am unable to reach the default gateway which is the interface on the firewall. I know it is something small I am missing but I can't quite put my finger on it. The default gateway is currently set to (which is the v1 interface on the the firewall. I will post a text file of our config, any suggestions would be greatly appreciated! 

10 Replies 10

Level 1
Level 1

In the config you will see a SVI for vlan 5 that is set to but that was for our test network. Also, the firewall is plugged into gig ethernet 1/0/1

Hello @kcross ,

the following command

>> ip default-gateway

applies to device that have ip routing disabled.

IF your cat9300 has ip routing enabled you need to use a static default route like

ip route

or you need to enter

no ip routing

Assuming that is the FW IP address and that you can ping it from the switch

Hope to help



The issue is I am unable to ping the firewall at when I should be able to 


can you share firewall config (at least the interfaces)

-hope this helps-

interface GigabitEthernet1/0/21
 switchport trunk native vlan 3
 switchport trunk allowed vlan 3,6
 switchport mode trunk

native VLAN 3 ??? why you change the native vlan ?
why vlan 1 not allow ??

Need to remove this, all vlan traffic should be tagged

sorry I dont get? can you more elaborate ?

The native vlan 3 should not be there, that portion I will need to remove


when you check the VLAN allow in trunk do you see VLAN 1 ??
I see in your config only VLAN3 and 5 there is no VLAN1?

for native vlan 3, I see trunk native vlan1 and other trunk native vlan3, 
this sure issue for SW and forwarding frame that receive it untag. 

Level 1
Level 1


here are the interfaces on the firewall

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