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philb19

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default gateway L2 switch

Hi,

Want to get my head around default gateway on L 2 switch.

ok 3 VLANs on L2 switch. vlan 2 vlan 3
vlan 4 is reachable through route

I have management on vlan 2 - I have an IP address 192.168.2.1 on vlan 2
I have an IP address on vlan 3 - 192.168.3.1 - I can ssh to manage switch on both of these IPs on vlan 2 and 3
vlan 4 is 192.168.4.0/24
my default gateway on the L2 switch is to my L3 switch  IP 192.168.3.3

I ssh to the L2 switch on vlan 2 192.168.2.1.   Can I then from this ssh session on the switch ping to VLAN 4
the default gateway L2 is not on VLAN 2 ?  Does it matter that I have come into the L2 switch by ssh  on vlan 2 - or do i need to ssh to VLAN 3 which has an IP on same subnet as the L2 gateway in order to ping another VLAN ??  - when I try to ping an IP on vlan 4   does it use the default gateway set on the L2 switch?

thanks
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Don Johnston
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I'm really having a difficult time following you...

If you have a true layer-2 switch, then you can only have one SVI (VLAN interface) up.  

So I don't understand how you have IP addresses on multiple VLANs.

And the default gateway has to be on the same network as the host.
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philb19

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Actually Ive just confused myself I think
correct me if wrong
The default gateway on a L2 switch is just for management traffic. And its just the gateway for that subnet only. ie gateway of the IP range that its on. So default gateway 192.168.2.254 on a L2 switch  is gateway for 192.168.2.0/24 "only" - otherwise its not used.

The gateway for VLAN 3 on 193.168.3.0/24 - would need to be on 192.168.3.0/24 and be a router interface.  When I ssh to Vlan3 and ping different subnet Id go via the gateway for this vlan. This question rose into my head as somehow we got couldn't reach a L2 switch management IP - and it was due to its default router not being on the management range IP subnet.

"If you have a true layer-2 switch, then you can only have one SVI (VLAN interface) up. " - here im not sure about. - We definitely have a L2 stack with multiple vlan interfaces on it. I can ssh to both of these interface IPs example vlan 3 192.168.3.1 and vlan 2 192.168.2.1 ?? - and im on the same switch
Save all the back and forth, would be easier if you just give make and model of switch.
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Cisco 2960 sstack
ASKER CERTIFIED SOLUTION
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Don Johnston
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sorry should have explained myself better

The gateway for VLAN 3 on 193.168.3.0/24...

the gateway for vlan 3 is via trunked uplink  to the L3 core- the gateway resides itself on the L3 router core.

thanks very much for detailed explanation - awesome help