diff --git a/src/devices/nm-device-ethernet.c b/src/devices/nm-device-ethernet.c
index 2f9a092a0f..4fc32c38f2 100644
--- a/src/devices/nm-device-ethernet.c
+++ b/src/devices/nm-device-ethernet.c
@@ -306,14 +306,18 @@ static NMDeviceCapabilities
 get_generic_capabilities (NMDevice *device)
 {
 	NMDeviceEthernet *self = NM_DEVICE_ETHERNET (device);
+	int ifindex = nm_device_get_ifindex (device);
 
-	if (nm_platform_link_supports_carrier_detect (NM_PLATFORM_GET, nm_device_get_ifindex (device)))
-	    return NM_DEVICE_CAP_CARRIER_DETECT;
-	else {
-		_LOGI (LOGD_PLATFORM, "driver '%s' does not support carrier detection.",
-		       nm_device_get_driver (device));
-		return NM_DEVICE_CAP_NONE;
+	if (ifindex > 0) {
+		if (nm_platform_link_supports_carrier_detect (NM_PLATFORM_GET, ifindex))
+			return NM_DEVICE_CAP_CARRIER_DETECT;
+		else {
+			_LOGI (LOGD_PLATFORM, "driver '%s' does not support carrier detection.",
+			       nm_device_get_driver (device));
+		}
 	}
+
+	return NM_DEVICE_CAP_NONE;
 }
 
 static guint32
diff --git a/src/devices/nm-device-generic.c b/src/devices/nm-device-generic.c
index 60afb6753d..2f51c69dd5 100644
--- a/src/devices/nm-device-generic.c
+++ b/src/devices/nm-device-generic.c
@@ -56,7 +56,9 @@ G_DEFINE_TYPE (NMDeviceGeneric, nm_device_generic, NM_TYPE_DEVICE)
 static NMDeviceCapabilities
 get_generic_capabilities (NMDevice *dev)
 {
-	if (nm_platform_link_supports_carrier_detect (NM_PLATFORM_GET, nm_device_get_ifindex (dev)))
+	int ifindex = nm_device_get_ifindex (dev);
+
+	if (ifindex > 0 && nm_platform_link_supports_carrier_detect (NM_PLATFORM_GET, ifindex))
 		return NM_DEVICE_CAP_CARRIER_DETECT;
 	else
 		return NM_DEVICE_CAP_NONE;