Layer 3 Switch InterVlan Routing

[calderonl.odari11]

I have a Cisco Catalyst 3560G Series POE layer 3 switch. I created two VLANs within the Layer 3 switch and provided them both with their respective IP address and net mask. For some reason I am still able to ping both of these VLANs even without the ip routing command. I access the switch with a console cable. Can anyone help ??? 

[prefixlength]

Hi, can you please post the switch configuration?

Also please elaborate on the source of the pings, possibly post a diagram of your topology too.

Cheers;

[Rob Burchard · Accepted solution]

Hi calderonl.odari11,

The "ip routing" command would have an affect on through-the-box IPv4 traffic forwarding between different vlans on the switch. As an example, If you were attempting to ping between two hosts on two different vlans/subnets that were connected to the switch, I would expect the ping to fail without the 'ip routing' command. With the 'ip routing' command enabled you would see two connected routes with the 'show ip route' command and you would be able to ping between those hosts.

However if you are attempting to ping an interface IP from the switch console, as long as the interface vlan is up/up the ping will be successful.

Hope this helps!

Rob

[calderonl.odari11]

Thank you.

[calderonl.odari11]

Thanks! 

[paul driver]

Hello

Possibly due to proxy arp being enabled so then switch is able to reply to the hosts arp broadcast stating it knows how to reach the other vlan.

sh ip int vlan xx