Want to disable L3 features on 3750G series

[shahanad20]

I have a catalyst 3750G series PoE 24 switch and an IP encryptor device. Unfortunately this IP encryptor device won't communicating with the switch. When I contacted their customer support, they telling that it will communicate only with L2 switch, so I tried using one L2 switch, it's worked. So I want to disable the L3 features on this. Anyone please help..

[Meheretab Mengistu]

Hi,

How about starting by disabling routing? Here is the command:-

conf t

no ip routing

end

wr mem

[shahanad20]

I have tried this, no change

[Meheretab Mengistu]

Thank you for trying it! What is the model of the L2 switch you tested with? Could you also share the output of the running config on the L2 switch.

[balaji.bandi]

you need to think is this device in the Live environment, is there any device connected to this switch, by Make Layer 2 means you messing up all the network connection here.

if you think this can be done without issue.

connect to console make changes, since once you make layer 2 u no longer able to access the switch you need to set up the default gateway to reach the switch.

to suggest best  - post-show run will advise.

On another note, you make a separate VLAN only for the Layer 2 connection between the device and another device that will also another solution you can think of.

[shahanad20]

It's not connected to any network, it's in a lab environment for testing
purpose.

[shahanad20]

I tried by adding that sfp port in a separate vlan and making as an access port, still that port not turning on when I connect this IP encryptor. This switch don't have any other configurations, everything reseted.

[balaji.bandi]

For testing create another VLAN X associated to port and connect the device to that port to act as Layer 2

or post -  show run

[shahanad20]

Tried the same. No difference.

[bradnorman]

To create another VLAN X associated to port and to connect your device to that port as Layer 2 use the following guide:

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/45002-intervlan3750-45002.html

essaydune.com

[shahanad20]

I'm using a fiber cable from that IP encryptor to this switch, I have tried by changing the SFP modules too, for checking SFP having any compatibility issue or not, but it's not made any change

[paul driver]

Hello

Is this a fibre copper SFP connection?
Can post the config of the switch please
sh run
sh interface transceiver
sh ip route
sh arp
sh mac address interface x/x
sh int x/x
sh int x/x switchport
sh version

[shahanad20]

I'm attaching an image of my laptop screen, on that you can see two switch port configurations which belongs to the L2 and L3 switches. Left side image (putty window) showing the switchport configuration of the port where I connected my ip encryptor using sfp module(not working) and right side image (notepad) showing the switchport configuration of the port where I connected ip encryptor (working).

L2 switch I'm using catalyst 2960 and L3 switch is 3750G

[Meheretab Mengistu]

When it was working, the interface was on default configuration and used auto negotiation to negotiate static ports. And when it was not working, the interface was configured as a static port. I do not think that has any impact (at least for now).

Please share the output of the following commands:

show vlan brief

show interface gi1/0/26

show interface status | i 1/0/26

show interface trunk