---
name: vpc-vni-known-issues
title: Known issues for virtual network interfaces
description: Known issues are identified bugs or unexpected behaviors that were not fixed before release, but weren’t critical enough to delay it. These issues are communicated to you, often with workarounds, and are prioritized for resolution in the near term by the development team.
last-updated: 2025-09-16
---

> ## Documentation Index
> The table of contents for this documentation set is at https://cloud.ibm.com/docs/vpc?format=markdown
> The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt
> Use these files to discover more information as needed.

# Known issues for virtual network interfaces
{: #vni-known-issues}

Known issues are identified bugs or unexpected behaviors that were not fixed before release, but weren’t critical enough to delay it. These issues are communicated to you, often with workarounds, and are prioritized for resolution in the near term by the development team.
{: shortdesc}

Known issues for virtual network interfaces are as follows:

* Not all virtual network interface targets support all virtual network interface policies.  
* Floating IP limitations:
   * With infrastructure NAT enabled for a virtual network interface, no more than one floating IP can target the virtual network interface. 
   * A floating IP cannot target a virtual network interface that is attached to a file share mount target.
   * When a floating IP is attached to a virtual network interface, network address translation (NAT) is performed between the floating IP’s public address and the virtual network interface’s primary IP address.
* Infrastructure NAT constraints:
   * Virtual server instances do not support disabling infrastructure NAT.
   * The `enable_infrastructure_nat` property cannot be `false` when the target is an instance network attachment or a file share mount target.
* Allow IP spoofing restrictions:
   * Creating an instance group from an instance template that has a virtual network interface with `allow_ip_spoofing` set to `true` is not yet supported.
   * The `allow_ip_spoofing` property cannot be `true` when the target is a file share mount target.
* File share mount target limitations:
   * The `protocol_state_filtering_mode` property cannot be `disabled` when the target is a file share mount target.
   * Secondary IP addresses are not allowed when the target is a file share mount target.
* Flow log collector constraints:
   * A flow log collector cannot target a virtual network interface that is attached to a bare metal server network attachment or a file share mount target.
   * Select customers have access to virtual server instances with vNICs that are SR-IOV enabled. Flow log collectors cannot target instance network attachments (nor child network interfaces) that are SR-IOV enabled.