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what is the use of auto Qos Trust command ?


Hi Team , 


We have below QOS configuration on one of the interface , Can someone explain me how this works ? With and without this configuration on the interface connecting to end device like CAMERA or PRINTER ? 



auto qos trust
service-policy input AutoQos-4.0-Trust-Cos-Input-Policy
service-policy output AutoQos-4.0-Output-Policy


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Auto QOS make life simpler again depending on use cases, below are some good explanation from cisco :



see the Camera and another device example:


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Can you confirm if qos is not configured on one of the interface where the printer is connected will it have any impact ? Or will it not allow the printer to get the ip assigned from the dhcp ? 
we learn mac on the interface but I don’t see ip arp on the l3 switch ..

Will this issue be due to auto qos not being configured on the interface ???


yes, you can do if the device does not require QoS like a printer makes it a simple config on the port. and yes device gets an IP address from DHCP.



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Apr 13 08:34:28.114: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPACK, MAC sa: 0023.047f.4c3c


On the L2 (9200 IOS-XE) switch I see this message . This 0023.047f.4c3c is learned from uplink interface Gi1/0/1 of L2 switch and belongs to svi vlan10 MAC.

And on vlan10 we have Ip helper configured , so our dhcp is on windows server . 


Can you please suggest what can be checked further or any configuration change has to be done. .