SG350x vlan interface automatically changes to trunk on first connection.

[AngeloAllary27264]

Hi,

Ik have 3 SG350x switches stacked with 6 Vlan's configured.

on first connection of a device to a port in a VLAN the switch automatically configures the interface to a trunk port instead of a access port.

This is not e wanted behaviour.

Which feature does this and how can i prevent it.

Thx !

[balaji.bandi]

we are not sure what port you referring, can you please post the screenshot to understand or refer below document can help you :

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350x-series-stackable-managed-switches/smb5408-configure-stack-settings-on-an-sg350x-switch.html

[AngeloAllary27264]

Before any PC has been connected to port 5 in the switch, this port is confugured as Access port:

After the connection of a pc to port 5, the Interface VLAN Mode is automatically set to Trunk.

[Georg Pauwen · Accepted solution]

Hello,

could be related to auto smartport. Try and disable that feature:

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350x-series-stackable-managed-switches/smb5247-configuring-smartports-on-the-sg350xg-and-sg550xg.html

[balaji.bandi]

Smart-port config detault enable - so disable.

[AngeloAllary27264]

That was it !

Many thanks.