> Source: [sk180634](https://support.checkpoint.com/results/sk/sk180634)

# sk180634 - IPv6 neighbor solicitation fails on several Maestro Security Gateway Modules (SGMs)

| Property | Value |
|----------|-------|
| Solution ID | sk180634 |
| Date Created | 2023-02-16 |
| Last Modified | 2023-04-17 |
| Technical Level | General |
| Products | Scalable Platforms |
| Versions | R81.10 (EOS) |
| OS | Gaia |

## Symptoms

- * When all Security Gateway Modules (SGMs) are UP on the active site, "`g_all ip -6 neighbor`" shows IPv6 neighbors as FAILED on some SGMs.

* Some IPv6 traffic works and some does not work when all SGMs are UP on the active site.

* All IPv6 traffic works correctly when the active Security Group or site has only one SGM as UP.

## Cause

Neighbor discovery fails because the reply does not arrive at the SGM which sent the request.  

Output of tcpdump:  

**[2_04]**`15:53:21.703978 IP6 2XX0:4bX0:f020:f02::14 > 2XX0:4bX0:f020:f02::1: ICMP6, echo request, seq 98, length 64 `  
**[2_01]**`15:53:21.710423 IP6 2XX0:4bX0:f020:f02::1 > 2XX0:4bX0:f020:f02::14: ICMP6, echo reply, seq 98, length 64 `  
`[2_04]15:53:22.704054 IP6 2XX0:4bX0:f020:f02::14 > 2XX0:4bX0:f020:f02::1: ICMP6, echo request, seq 99, length 64 `  
`[2_01]15:53:22.710461 IP6 2XX0:4bX0:f020:f02::1 > 2XX0:4bX0:f020:f02::14: ICMP6, echo reply, seq 99, length 64 `

This is the reason for the incomplete IPv6 neighbor discovery process on several SGMs:

(Click on the image to enlarge it.)  
![](https://sc1.checkpoint.com/sc/SolutionsStatics/sk180634/IPv6-neighbor error202302212137372.png)

## Solution

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

* [Check Point R81.20](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk177624&partition=Basic&product=Quantum)
* [Jumbo Hotfix Accumulator for R81.10](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk175186&partition=Basic&product=All) starting from Take 95

Check Point recommends to always upgrade to the [Recommended version](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk95746) ([Security Gateway](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doShowproductpage&productTab=downloads&product=435) / [VSX](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doShowproductpage&productTab=downloads&product=359) / [Security Management Server](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doShowproductpage&productTab=downloads&product=184) / [Multi-Domain Security Management Server](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doShowproductpage&productTab=downloads&product=166) / [SmartConsole](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doShowproductpage&productTab=downloads&product=191)).

If you choose not to upgrade, [contact Check Point Support](https://www.checkpoint.com/support-services/contact-support/) to get a Hotfix for your version.

A Support Engineer will make sure the Hotfix is compatible with your environment before providing it.  
For faster resolution and verification, collect [CPinfo](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk92739) files from the Management Server and Security Gateways / Cluster Members involved in the case.

**Hotfix installation instructions:**   
Refer to [sk168597 - How to install a Hotfix](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk168597).

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