# Anti-Spoofing drops IPv6 traffic that arrives at an interface with an IPv6 address configured

**Product**: Security Gateways  
**Version**: R81.10 (EOS), R81.20, R82  
**OS**: Gaia  
**Platform**: Open Server  
**Last Modified**: 2025-01-27

## Symptoms

- Anti-Spoofing drops IPv6 traffic that arrives at an interface with an IPv6 address configured. The logs show:
  
  ```
  @;272246227;[kern];[tid_37];[SIM-241695243];sim_pkt_send_drop_notification: sending single drop notification, conn: <2001:b68:ff:12:4605:4035:f5a0:1867,6,fdca:0:0:2:0:0:32:2,128,58>;
  @;272246227;[kern];[tid_37];[SIM-241695243];do_packet_finish: SIMPKT_IN_DROP vsid=2, conn:<2001:b68:ff:12:4605:4035:f5a0:1867,6,fdca:0:0:2:0:0:32:2,128,58>;
  @;37145111;[vs_2];[tid_0];[fw6_0];cphwd_notif_packet_dropped: received packet dropped notification, reason: Anti-Spoofing;
  @;37145111;[vs_2];[tid_0];[fw6_0];cphwd_notif_packet_dropped: notification holds a single drop;
  ```

## Cause

The IPv6 addresses were miscalculated when exceptions were added from the external interface.

## Solution

This problem was fixed. The fix is included in:

- [Jumbo Hotfix Accumulator for R82](https://sc1.checkpoint.com/documents/Jumbo_HFA/R82/Default.htm) starting from Take 10  
- [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 90  
- [Jumbo Hotfix Accumulator for R81.10](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.10/Default.htm) starting from Take 171

If you choose not to upgrade, Check Point can supply a **Hotfix**. [Contact Check Point Support](https://www.checkpoint.com/support-services/.contact-support/) to get a Hotfix for this issue.

A Support Engineer will make sure the Hotfix is compatible with your environment before providing the Hotfix.

For faster resolution and verification, please collect [CPinfo files](http://supportcontent.checkpoint.com/solutions?id=sk92739) from the Security Management Server and Security Gateways 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).

#### NOTE

This solution has been verified for the specific scenario, described by the combination of Product, Version and Symptoms. It may not work in other scenarios.