> Source: [sk183876](https://support.checkpoint.com/results/sk/sk183876)

# sk183876 - IPv6 address is not assigned to local networks on Spark Firewall after enabling Prefix Delegation

| Property | Value |
|----------|-------|
| Solution ID | sk183876 |
| Date Created | 2025-08-30 |
| Last Modified | 2025-09-01 |
| Technical Level | General |
| Products | Spark Firewall (Locally Managed) |
| Versions | R81.10.X |
| Platform | 1500, 1900, 2000, 1600, 1800 |

## Symptoms

- * The system does not automatically assign IPv6 addresses to local networks after you enable Prefix Delegation.

* The default IPv6 Auto Assignment mode changes from Stateless Address Autoconfiguration (SLAAC) to Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Server when editing Local Area Network (LAN) ports.

* You must manually change the IPv6 Auto Assignment mode back to SLAAC for IPv6 assignment to work as expected.

* An input error may occur when saving port configuration if you do not manually adjust the settings.

## Cause

The behavior described in the symptoms is not an intentional product change. The default mode should remain SLAAC. A software issue in the affected builds caused the observed behavior.

## Solution

This problem was fixed. The fix is included starting from:

* [R81.10.17 for Quantum Spark Appliances](https://support.checkpoint.com/results/sk/sk179615) Build 4693 or Above

After you apply the fix:

1. Edit the LAN port configuration and enable Prefix Delegation.
2. Confirm that the IPv6 Auto Assignment mode is SLAAC.
3. Save the configuration and verify that IPv6 addresses are automatically assigned to local networks as expected.

If you choose not to upgrade, apply this **workaround** :  

When editing LAN port settings, manually set the IPv6 Auto Assignment mode to SLAAC before saving.  

**Notes** :  

* The procedure includes a reboot request.
* If you experience input errors when saving the port configuration, make sure that the IPv6 Auto Assignment mode is set to SLAAC.
* This issue only affects Quantum Spark Appliances running version R81.10.17 prior to the specified hotfix builds.

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content