The DGS-3100 has a slightly more complex VLAN setup, hence, the exact steps are as follows if you want to allow all LAN ports access to the Switch configuration (in this instance, you would use a computer on Ports 2-32 or 43-47 to access the switch management):
Go to L2 -> Asymmetric VLAN and enable it.
Go to L2 Features > Forward & Filtering >DLF Filtering Mode:
Select All (check the box), Select Forward all DLF packets.
Apply.
Go to L2 -> 802.1Q VLAN:
Edit Default VLAN (VID 1).
Select Ports 1 & 33-42 as non-members.
Select Ports 2-32, 43-47 as untagged.
Click Apply.
Click on the Add/ Edit VLAN tab.
Add a new VLAN with VID = 2, Name = LAN.
Select Port 1 as Tagged.
Select Ports 2-32 as Untagged.
Select Ports 33-48 as Non-member.
Click Apply.
Click on the Add/ Edit VLAN tab.
Add a new VLAN with VID = 3, Name = Freeswitch.
Select Port 1 as Tagged.
Select Ports 33-42 as Untagged.
Select Ports 2-32, 43-48 as Non-Member.
Click Apply.
Click on the Add/ Edit VLAN tab.
Add a new VLAN with VID = 4, Name = Wifi.
Select Port 1 as Tagged.
Select Port 48 as Untagged.
Select Ports 2-47 as Non-Member.
Click Apply.