Disabled Mail Sending from VM

[Amori]

Hello!

I was looking for the correct configuration in the Proxmox Interface for Blocking mail for a VM.
I have changed settings for firewall on DataCenter to Enabled, like

Then added a rule in Firewalll, Out, Drop, Macro Mail.

is that enough?

 

[LnxBil]

You also need to add the flag firewall to the NIC in the hardware tab.

I'd also use REJECT instead of DROP, better response times for applications.