diff --git a/proxmox/perf/scripts/add-datanet-nics.sh b/proxmox/perf/scripts/add-datanet-nics.sh
new file mode 100644
index 0000000..e36cff6
--- /dev/null
+++ b/proxmox/perf/scripts/add-datanet-nics.sh
@@ -0,0 +1,96 @@
+#!/bin/bash
+###############################################################################
+# add-datanet-nics.sh
+#
+# Adds a second virtio NIC (net1) to all k8s + ultix VMs, bridged to the
+# storage/datanet network (VLAN 1000). Records the assigned IP in phpIPAM.
+#
+# Runs from the workstation — uses tests/remote.sh to reach each hypervisor.
+# Hot-adds the NIC (no VM downtime). Guest-side IP config must be done
+# separately (the guest OS needs the IP configured on the new interface).
+#
+# Usage:
+#   bash add-datanet-nics.sh             # add NICs (hot-add, no reboot)
+#   bash add-datanet-nics.sh --status    # show current state only
+#
+# IP allocations (phpIPAM VPTechOps, subnet 10.100.100.0/24):
+#   .10 = cnode1    (102/tsys1)
+#   .11 = cnode2    (705/tsys7)
+#   .12 = cnode3    (603/tsys6)
+#   .13 = wnode-tsys3 (313/tsys3)
+#   .14 = wnode-tsys5 (500/tsys5)
+#   .15 = wnode-tsys6 (601/tsys6)
+#   .16 = wnode-tsys7 (701/tsys7)
+#   .17 = wnode-tsys9 (905/tsys9)
+#   .18 = ultix-streaming (5111/tsys5)
+#   .19 = ultix-offstage  (5112/tsys5)
+#
+# Related: Redmine [#396]
+###############################################################################
+set -euo pipefail
+
+# VM definitions: VMID HOST BRIDGE IP HOSTNAME
+VMS=(
+    "102  tsys1  datanet      10.100.100.10  pfv-k8s-cnode1"
+    "705  tsys7  datanet      10.100.100.11  pfv-k8s-cnode2"
+    "603  tsys6  storagenet   10.100.100.12  pfv-k8s-cnode3"
+    "313  tsys3  datanet      10.100.100.13  pfv-k8s-wnode-tsys3"
+    "500  tsys5  datanet      10.100.100.14  pfv-k8s-wnode-tsys5"
+    "601  tsys6  storagenet   10.100.100.15  pfv-k8s-wnode-tsys6"
+    "701  tsys7  datanet      10.100.100.16  pfv-k8s-wnode-tsys7"
+    "905  tsys9  datanet      10.100.100.17  pfv-k8s-wnode-tsys9"
+    "5111 tsys5  datanet      10.100.100.18  ultix-streaming"
+    "5112 tsys5  datanet      10.100.100.19  ultix-offstage"
+)
+
+ACTION="${1:-add}"
+
+echo "==================================================================="
+echo " add-datanet-nics — [#396]"
+echo " mode: ${ACTION}"
+echo "==================================================================="
+echo ""
+
+for entry in "${VMS[@]}"; do
+    read -r vmid host bridge ip hostname <<< "$entry"
+    prox_host="pfv-${host}"
+
+    echo "--- ${hostname} (VM ${vmid} on ${prox_host}) ---"
+
+    if [ "$ACTION" = "--status" ]; then
+        # Show current NIC state
+        PROX_HOST="$prox_host" bash tests/remote.sh prox \
+            "qm config ${vmid} 2>/dev/null | grep -E '^net|^name'" 2>&1
+        echo ""
+        continue
+    fi
+
+    # Check if net1 already exists
+    existing=$(PROX_HOST="$prox_host" bash tests/remote.sh prox \
+        "qm config ${vmid} 2>/dev/null | grep '^net1'" 2>&1 || true)
+
+    if [ -n "$existing" ]; then
+        echo "  net1 already exists: ${existing}"
+        echo "  Skipping."
+        echo ""
+        continue
+    fi
+
+    # Hot-add net1 bridged to the storage network
+    echo "  Adding net1 (bridge=${bridge}, IP=${ip})..."
+    if PROX_HOST="$prox_host" bash tests/remote.sh prox \
+        "qm set ${vmid} -net1 virtio,bridge=${bridge}" 2>&1; then
+        echo "  NIC added. Verify with: qm config ${vmid} | grep net1"
+    else
+        echo "  FAILED — check error above"
+    fi
+    echo ""
+done
+
+if [ "$ACTION" != "--status" ]; then
+    echo "==================================================================="
+    echo " NICs added. Guest-side IP config still needed."
+    echo " Each guest needs the IP configured on the new interface."
+    echo " IPs are allocated in phpIPAM (VPTechOps / 10.100.100.0/24)."
+    echo "==================================================================="
+fi