Different subnet source traffic entering an SVI

[tedauction]

Hello, if I have an SVI with an IP address of 192.168.1.1/24 and source traffic coming in to that SVI with source subnet addressing of 192.168.2.x/24 will the SVI still route it, or will it drop it ?

Thank you.

[Reza Sharifi]

Hi,

If you have an SVI with IP 192.168.1.1/24, whatever end device in the LAN that is part of that SVI needs to be on the same subnet.

HTH

[Julio E. Moisa]

Hi

I assume the source traffic is over the same VLAN like the SVI, right? In this case I agree with Reza, the source should be over the same network segment like the SVI, but also you could have something like:

PC- VLAN 10 with IP 192.168.2.225

Switch

VLAN 10

name LAN

interface VLAN 10

ip address 192.168.1.1 255.255.255.0

ip address 192.168.2.1 255.255.255.0 secondary

So the traffic from the source will not be discarded because it will part of the same SVI.

Hope it is useful

:-)

[Jon Marshall · Accepted solution]

Not exactly clear what you mean by source traffic. 

If you mean traffic coming into that SVI from a client in that vlan then yes it should be routed because L3 devices route based on the destination IP. 

After all that vlan could be a transit vlan ie. other L3 devices connected to it so source IPs could be anything. 

Jon