diff --git a/main.tf b/main.tf
index 0b991382..78efc99a 100644
--- a/main.tf
+++ b/main.tf
@@ -20,9 +20,9 @@ locals {
   }, var.tags)
 }
 
-# ------------------------------------------------------------
+# COMMON NETWORKING -------------------------------------------
 
-# TODO: To be moved in another module
+# TODO: To be moved in another module ?
 
 resource "azurerm_resource_group" "graphdb" {
   name     = var.resource_name_prefix
@@ -60,6 +60,57 @@ resource "azurerm_subnet" "graphdb-vmss" {
   address_prefixes     = var.graphdb_subnet_address_prefix
 }
 
+resource "azurerm_network_security_group" "graphdb-gateway" {
+  name                = "${var.resource_name_prefix}-gateway"
+  resource_group_name = azurerm_resource_group.graphdb.name
+  location            = var.location
+
+  security_rule {
+    name                       = "AllowGatewayManager"
+    description                = "Allows Gateway Manager to perform health monitoring."
+    priority                   = 100
+    direction                  = "Inbound"
+    access                     = "Allow"
+    protocol                   = "Tcp"
+    source_address_prefix      = "GatewayManager"
+    source_port_range          = "*"
+    destination_address_prefix = "*"
+    destination_port_range     = "65200-65535"
+  }
+
+  security_rule {
+    name                         = "AllowInternetInbound"
+    description                  = "Allows inbound internet traffic to the gateway subnet."
+    priority                     = 1000
+    direction                    = "Inbound"
+    access                       = "Allow"
+    protocol                     = "Tcp"
+    source_address_prefix        = "Internet"
+    source_port_range            = "*"
+    destination_address_prefixes = var.app_gateway_subnet_address_prefix
+    destination_port_ranges      = [80, 443]
+  }
+
+  tags = var.tags
+}
+
+resource "azurerm_network_security_group" "graphdb-vmss" {
+  name                = "${var.resource_name_prefix}-vmss"
+  resource_group_name = azurerm_resource_group.graphdb.name
+  location            = var.location
+  tags                = var.tags
+}
+
+resource "azurerm_subnet_network_security_group_association" "graphdb-gateway" {
+  network_security_group_id = azurerm_network_security_group.graphdb-gateway.id
+  subnet_id                 = azurerm_subnet.graphdb-gateway.id
+}
+
+resource "azurerm_subnet_network_security_group_association" "graphdb-vmss" {
+  network_security_group_id = azurerm_network_security_group.graphdb-vmss.id
+  subnet_id                 = azurerm_subnet.graphdb-vmss.id
+}
+
 # ------------------------------------------------------------
 
 # Creates a public IP address with assigned FQDN from the regional Azure DNS
@@ -166,11 +217,13 @@ module "bastion" {
 
   source = "./modules/bastion"
 
-  resource_group_name           = azurerm_resource_group.graphdb.name
-  location                      = var.location
+  resource_name_prefix = var.resource_name_prefix
+  location             = var.location
+  resource_group_name  = azurerm_resource_group.graphdb.name
+
   virtual_network_name          = azurerm_virtual_network.graphdb.name
-  resource_name_prefix          = var.resource_name_prefix
   bastion_subnet_address_prefix = var.bastion_subnet_address_prefix
+  bastion_allowed_cidr_blocks   = var.management_cidr_blocks
 
   tags = local.tags
 }
@@ -199,8 +252,7 @@ module "vm" {
   resource_group_id    = azurerm_resource_group.graphdb.id
   zones                = var.zones
 
-  graphdb_subnet_id   = azurerm_subnet.graphdb-vmss.id
-  graphdb_subnet_cidr = one(azurerm_subnet.graphdb-vmss.address_prefixes)
+  graphdb_subnet_id = azurerm_subnet.graphdb-vmss.id
 
   identity_id                                  = module.identity.identity_id
   identity_principal_id                        = module.identity.identity_principal_id
@@ -214,11 +266,10 @@ module "vm" {
   disk_mbps_read_write = var.disk_mbps_read_write
   disk_size_gb         = var.disk_size_gb
 
-  instance_type     = var.instance_type
-  image_id          = module.graphdb_image.image_id
-  node_count        = var.node_count
-  ssh_key           = var.ssh_key
-  source_ssh_blocks = var.source_ssh_blocks
+  instance_type = var.instance_type
+  image_id      = module.graphdb_image.image_id
+  node_count    = var.node_count
+  ssh_key       = var.ssh_key
 
   custom_user_data = var.custom_graphdb_vm_user_data
 
diff --git a/modules/bastion/main.tf b/modules/bastion/main.tf
index bb973ef3..7c2e5df6 100644
--- a/modules/bastion/main.tf
+++ b/modules/bastion/main.tf
@@ -1,11 +1,84 @@
-resource "azurerm_subnet" "graphdb-bastion-subnet" {
+resource "azurerm_subnet" "graphdb-bastion" {
   name                 = "AzureBastionSubnet"
   resource_group_name  = var.resource_group_name
   virtual_network_name = var.virtual_network_name
   address_prefixes     = var.bastion_subnet_address_prefix
 }
 
-resource "azurerm_public_ip" "graphdb-bastion-public-ip" {
+resource "azurerm_network_security_group" "graphdb-bastion" {
+  name                = "${var.resource_name_prefix}-bastion"
+  resource_group_name = var.resource_group_name
+  location            = var.location
+
+  # The following rules are required by Azure Bastion in order to function properly
+  # See https://learn.microsoft.com/en-us/azure/bastion/bastion-nsg
+  # See https://learn.microsoft.com/en-gb/azure/bastion/native-client#secure
+
+  # INBOUND
+
+  security_rule {
+    name                       = "AllowHTTPSInternetInbound"
+    description                = "Allows specified CIDRs to access the Bastion subnet"
+    priority                   = 100
+    direction                  = "Inbound"
+    access                     = "Allow"
+    protocol                   = "Tcp"
+    source_address_prefixes    = var.bastion_allowed_cidr_blocks
+    source_port_range          = "*"
+    destination_address_prefix = "*"
+    destination_port_range     = 443
+  }
+
+  security_rule {
+    name                       = "AllowGatewayManagerInbound"
+    description                = "Allows Gateway Manager to perform system operations"
+    priority                   = 110
+    direction                  = "Inbound"
+    access                     = "Allow"
+    protocol                   = "Tcp"
+    source_address_prefix      = "GatewayManager"
+    source_port_range          = "*"
+    destination_address_prefix = "*"
+    destination_port_range     = 443
+  }
+
+  # OUTBOUND
+
+  security_rule {
+    name                       = "AllowSSHOutbound"
+    description                = "Allows outbound SSH/RDP connections"
+    priority                   = 100
+    direction                  = "Outbound"
+    access                     = "Allow"
+    protocol                   = "*"
+    source_address_prefix      = "*"
+    source_port_range          = "*"
+    destination_address_prefix = "VirtualNetwork"
+    destination_port_ranges    = [22, 3389]
+  }
+
+  security_rule {
+    name                       = "AllowAzureCloudOutbound"
+    description                = "Allows outbound connections to Azure Cloud services"
+    priority                   = 110
+    direction                  = "Outbound"
+    access                     = "Allow"
+    protocol                   = "Tcp"
+    source_address_prefix      = "*"
+    source_port_range          = "*"
+    destination_address_prefix = "AzureCloud"
+    destination_port_range     = 443
+  }
+
+  tags = var.tags
+}
+
+resource "azurerm_subnet_network_security_group_association" "graphdb-bastion" {
+  network_security_group_id = azurerm_network_security_group.graphdb-bastion.id
+  subnet_id                 = azurerm_subnet.graphdb-bastion.id
+}
+
+resource "azurerm_public_ip" "graphdb-bastion" {
   name                = "${var.resource_name_prefix}_bastion_publicIP"
   location            = var.location
   resource_group_name = var.resource_group_name
@@ -14,15 +87,19 @@ resource "azurerm_public_ip" "graphdb-bastion-public-ip" {
   tags                = var.tags
 }
 
-resource "azurerm_bastion_host" "graphdb-bastion-host" {
+resource "azurerm_bastion_host" "graphdb" {
   name                = "${var.resource_name_prefix}_bastion"
   location            = var.location
   resource_group_name = var.resource_group_name
 
+  # Enables additional features such as native client support (Azure CLI)
+  sku               = "Standard"
+  tunneling_enabled = true
+
   ip_configuration {
     name                 = "configuration"
-    subnet_id            = azurerm_subnet.graphdb-bastion-subnet.id
-    public_ip_address_id = azurerm_public_ip.graphdb-bastion-public-ip.id
+    subnet_id            = azurerm_subnet.graphdb-bastion.id
+    public_ip_address_id = azurerm_public_ip.graphdb-bastion.id
   }
 
   tags = var.tags
diff --git a/modules/bastion/variables.tf b/modules/bastion/variables.tf
index 30264aa1..04b8e1c2 100644
--- a/modules/bastion/variables.tf
+++ b/modules/bastion/variables.tf
@@ -33,3 +33,8 @@ variable "bastion_subnet_address_prefix" {
   type        = list(string)
   default     = ["10.0.3.0/27"]
 }
+
+variable "bastion_allowed_cidr_blocks" {
+  description = "CIDR blocks allowed for connecting to Bastion"
+  type        = list(string)
+}
diff --git a/modules/vm/main.tf b/modules/vm/main.tf
index 15e0490c..d15032d3 100644
--- a/modules/vm/main.tf
+++ b/modules/vm/main.tf
@@ -1,46 +1,3 @@
-# Create Network Security Group and rules
-resource "azurerm_network_security_group" "graphdb" {
-  name                = "${var.resource_name_prefix}-nic"
-  resource_group_name = var.resource_group_name
-  location            = var.location
-
-  tags = var.tags
-}
-
-resource "azurerm_network_security_rule" "graphdb-inbound-ssh" {
-  count = var.source_ssh_blocks != null ? 1 : 0
-
-  resource_group_name         = var.resource_group_name
-  network_security_group_name = azurerm_network_security_group.graphdb.name
-
-  name                       = "graphdb_ssh_inbound"
-  description                = "Allow specified CIDRs SSH access to the GraphDB instances."
-  priority                   = 900
-  direction                  = "Inbound"
-  access                     = "Allow"
-  protocol                   = "Tcp"
-  source_port_range          = "*"
-  destination_port_range     = 22
-  source_address_prefixes    = var.source_ssh_blocks
-  destination_address_prefix = var.graphdb_subnet_cidr
-}
-
-resource "azurerm_network_security_rule" "graphdb-proxies-inbound" {
-  resource_group_name         = var.resource_group_name
-  network_security_group_name = azurerm_network_security_group.graphdb.name
-
-  name                       = "graphdb_proxies_inbound"
-  description                = "Allow internet traffic to reach the GraphDB proxies"
-  priority                   = 1000
-  direction                  = "Inbound"
-  access                     = "Allow"
-  protocol                   = "Tcp"
-  source_port_range          = "*"
-  destination_port_range     = "7201"
-  source_address_prefixes    = ["0.0.0.0/0"]
-  destination_address_prefix = var.graphdb_subnet_cidr
-}
-
 locals {
   user_data_script = var.custom_user_data != null ? var.custom_user_data : templatefile("${path.module}/templates/entrypoint.sh.tpl", {
     graphdb_external_address_fqdn : var.graphdb_external_address_fqdn
@@ -76,10 +33,14 @@ resource "azurerm_linux_virtual_machine_scale_set" "graphdb" {
   computer_name_prefix = "${var.resource_name_prefix}-"
   admin_username       = "graphdb"
 
+  scale_in {
+    # In case of re-balancing, remove the newest VM which might have not been IN-SYNC yet with the cluster
+    rule = "NewestVM"
+  }
+
   network_interface {
-    name                      = "${var.resource_name_prefix}-vmss-nic"
-    primary                   = true
-    network_security_group_id = azurerm_network_security_group.graphdb.id
+    name    = "${var.resource_name_prefix}-vmss-nic"
+    primary = true
 
     ip_configuration {
       name                                         = "${var.resource_name_prefix}-ip-config"
@@ -104,6 +65,26 @@ resource "azurerm_linux_virtual_machine_scale_set" "graphdb" {
   depends_on = [azurerm_role_assignment.rg-contributor-role]
 }
 
+resource "azurerm_monitor_autoscale_setting" "graphdb-autoscale-settings" {
+  name                = "${var.resource_name_prefix}-vmss"
+  location            = var.location
+  resource_group_name = var.resource_group_name
+  target_resource_id  = azurerm_linux_virtual_machine_scale_set.graphdb.id
+
+  profile {
+    name = "${var.resource_name_prefix}-vmss-fixed"
+
+    # We want to keep a tight count for 3 node quorum
+    capacity {
+      default = var.node_count
+      maximum = var.node_count
+      minimum = var.node_count
+    }
+  }
+
+  tags = var.tags
+}
+
 resource "azurerm_role_definition" "managed_disk_manager" {
   name        = "ManagedDiskManager"
   scope       = var.resource_group_id
diff --git a/modules/vm/variables.tf b/modules/vm/variables.tf
index 13a5ae03..68f50c7b 100644
--- a/modules/vm/variables.tf
+++ b/modules/vm/variables.tf
@@ -39,11 +39,6 @@ variable "graphdb_subnet_id" {
   type        = string
 }
 
-variable "graphdb_subnet_cidr" {
-  description = "CIDR of the subnet where GraphDB will be deployed"
-  type        = string
-}
-
 # Security
 
 variable "identity_id" {
@@ -100,12 +95,6 @@ variable "ssh_key" {
   default     = null
 }
 
-variable "source_ssh_blocks" {
-  description = "CIDR blocks to allow SSH traffic from."
-  type        = list(string)
-  default     = null
-}
-
 variable "custom_user_data" {
   description = "Custom user data script used during the cloud init phase in the GraphDB VMs. Should be in base64 encoding."
   type        = string
diff --git a/variables.tf b/variables.tf
index eff5ffea..8a454cfc 100644
--- a/variables.tf
+++ b/variables.tf
@@ -48,6 +48,11 @@ variable "graphdb_subnet_address_prefix" {
   default     = ["10.0.2.0/24"]
 }
 
+variable "management_cidr_blocks" {
+  description = "CIDR blocks allowed to perform management operations such as connecting to Bastion or Key Vault."
+  type        = list(string)
+}
+
 # TLS
 
 variable "tls_certificate_path" {
@@ -125,12 +130,6 @@ variable "ssh_key" {
   default     = null
 }
 
-variable "source_ssh_blocks" {
-  description = "CIDR blocks to allow SSH traffic from."
-  type        = list(string)
-  default     = null
-}
-
 variable "custom_graphdb_vm_user_data" {
   description = "Custom user data script used during the cloud init phase in the GraphDB VMs. Should be in base64 encoding."
   type        = string