Blocking Communication on the Same Network Unless Specified

Hi Ciaran,

traffic within the same network does not pass the Firewall the source device uses its ARP Mechanisms to find the destination MAC and sends the packet to its destination.

only if the destination is outside the source network then it passes a L3 Device.

you can use Bridge Ports at your UTM on which you can build L2 Firewalling - but of course you have limitet ports to do so.

you'll end up with two or three "Zones"

for example

Bridgeinterface "LAN"

eth1, eth2, eth3

each member interface is connected to a separtae Switch

on the switch at eth1 you'll connect all clients

on eht2 you'll connect all servers

on eth3 the third "security Zone"

then you can build Firewall rules based on Mac Adresse / between the member zones.

thats all you can do with your UTM otherwise you need to use the destination devices local firewall "Windows Firewall / IPTables"

Yours Lukas

Hi Ciaran and welcome to the UTM Community!

Also, tell us what problem you're seeing that you want to address.

Cheers - Bob