I am lost at what my issue can be.   I have vonage phones that need to access their Adtran gateway for DHCP and to register in the cloud.  The phones are connected to user switches.  The user switches connect to my C3850X core switch.   The Core swit...

So I am requesting help from the Cisco community on this issue as the cable company states there equipment is working fine.  At all my facilities I have a guest Internet service setup through a local Internet provide to provide Internet services to t...