Port is UP. But Mac is unavailable.

[Weda]

We have a remote Summit X450G2-24t-G4 switch running XOS 21.1.1.4.
I can see a device (VOIP related device) is connected to a port (port is admin up and oper up).
But I cannot see the MAC when "show fdb" is given. What could be the reason ? Device is given a Static ip. (Not in ARP table too.)

[Jason_Parker]

is the item on a different VLAN than assigned (tagged 22 when it should using 33?
Is one side tagged vs. untagged

[simon_bingham]

I second this, Phone is in one VLAN, switch port does not have same vlan

[Bastian_Sprotte]

Hi Weda,
use the
show port 3 information detail
to verify that vlan is defined on the port as well as no STP blocking is happen.
these would 2 event that no FDB learing will happen.

also check if packets are send into the port via the statistics
show port 3 statistics no-refresh

-

[Henrique]

Hi Weda, Is it possible to connect a PC to that port and check?