cisco switch SG350-28 VLAN created all ports are in trunk mode but it automatically goes to trunk mode

[Tukaram]

cisco switch SG350-28 VLAN created all ports are in trunk mode but it automatically goes to trunk mode

[andresfr]

Hello Tukaram,

This question is not clear at all. Can you explain better what you're trying to achieve and the results that you're getting?

Regards,

[Giuseppe Larosa]

Hello Tukaram,

see the following thread

https://community.cisco.com/t5/switching/sg350-28-trunk-ports-not-holding-tagged-vlans/m-p/3822881

I have checked the command reference and this device should not support the DTP protocol that is used by Cisco IOS switches.

The DTP protocol mode desirable could make ports to negotiate and become trunks.

What is connected to the switch ports ?

Hope to help

Giuseppe

[babak.b.c@gmail.com]

Hi

Smart port feature is enabled which caused it. You can search "SmartPort" in SG350 and Disable it.