I have done this before on a Cisco switch but it’s been a while. Thought I share my notes on what commands are needed

# Vlan131 (fog server vlan) ip helper-address 192.168.158.255 # Vlan158 (fog client on a different vlan) ip directed-broadcast 101 # ip access-list extended 101 access-list 101 permit udp host 192.168.131.149 any eq 9 * NOTE in the ACL above 192.168.131.149 is the fog server ip address # forward udp ip forward protocol udp 9 (it might say discard) # On the switch the two vlans look something like this interface Vlan131 description fog server vlan ip address 192.168.131.1 255.255.255.0 ip helper-address 192.168.131.3 (my dhcp & dns server) ip helper-address 192.168.158.255 (fog client subnet broadcast address) end interface Vlan158 description fog client vlan ip address 192.168.158.1 255.255.255.0 ip directed-broadcast 101 (extended ACL) end

Hope it helps