diff --git a/web/support/FAQ.rst b/web/support/FAQ.rst
index cd49efe75f225fee9c949f737bdbad0fb9f65bde..ea25c94322d6ee6f7c023601d0d5c1e32a38fe9e 100644
--- a/web/support/FAQ.rst
+++ b/web/support/FAQ.rst
@@ -9,6 +9,39 @@ Operations
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+MAC address Issues detaching/attaching network interfaces 
+----------------------------------------------------------
+
+With recent Debian-based systems (e.g. Debian12, Ubuntu20+) detaching and re-attaching network interfaces to VMs can raise issues.
+
+The cause is that the MAC address of the NIC is hard-written in the netplan (/etc/netplan/netplan.yaml) file via cloud-init at instance creation. If the network interface is removed and reattached the system cannot assign the new MAC address, raising the following error on the console log::
+
+    ... stages.py[WARNING]: Failed to rename devices: [nic not present] Cannot rename mac=fa:16:3e:69:15:67 to ens3, not available.
+ 
+As a consequence, the VM is no longer reachable
+
+Here is the procedure to correctly detach a VM NIC from Network A and attach to Network B.
+
+  - On the OpenStack dashboard, go to Network -> Networks 
+  - Select the private network attached to the VM (Network A) and click on Ports
+  - Find the port attached to the VM (e.g. looking for the IP address) and copy the correspondent MAC address
+    - (alternatively: SSH log on the machine; cat file /etc/netplan/<netplan_name>.yaml and copy the MAC address)
+  - Important: Take note of the SECURITY GROUPS attached to the VM as they will get detached together with the NIC!
+  - Detach the interface from the VM: 
+    - go to Compute -> Instances; from the drop-down menu of the VM select Detach interface; on the pop-up windows select the IP address of the VM, then click Detach interface
+  - Go to  Network -> Networks, select the network to be attached to the VM (Network B), click on Ports 
+  - Click on Create Port
+  - On the pop-up window optionally choose a name for the port and PASTE the original MAC address in the MAC Address box
+  - Go back to the Instance page
+  - from the drop-down menu of the VM select Attach interface
+  - From the menu "The way to specify an Interface" select "By Port" and in the Port menu select the port previously created
+  - From the drop-down menu of the VM select Edit security Groups
+  - Re-add the security group previously attached to the VM
+  - Reboot the VM
+
+Now the VM is correctly attached to the new network!
+
+
 non-default (FAST and CAPACITY) volume types (garr-ct1 and garr-pa1 regions) 
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