# NAT-T traffic from VPN clients does not match implied rule

## Product
Endpoint Security - Remote Access VPN

## Version
R80.40 (EOS), R81 (EOS), R81.10 (EOS), R81.20

## Last Modified
2023-07-19

## Symptoms

- NAT-T traffic may stop matching the implied rule after policy installation and is dropped with "`IKE_NAT_TRAVERSAL Traffic Dropped from x.x.x.x to y.y.y.y`" message in SmartLog.
- VPN clients cannot connect to the gateway and fail with "`Negotiation with site failed`" message.

- The "`fw tab -t natt_port -u -f`" command does not show entry for NAT-T port. In working situation, it should show an entry with 1194 (HEX for port 4500)
- IKED debug shows IKED gets killed with signal 6 (SIGABRT). During the cleanup and exit it clears the natt_port table and restarts automatically
- Issue can happen after creating LDAP group object from Smart Console and pushing policy with the change

## Cause

Entry for NAT-T port (4500) is removed from the _natt_port_ table.

## Solution

This problem was fixed. The fix is included in:

- [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 8
- [Jumbo Hotfix Accumulator for R81.10](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.10/Default.htm) starting from Take 95
- [Jumbo Hotfix Accumulator for R81](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81/Default.htm) starting from Take 82
- [Jumbo Hotfix Accumulator for R80.40](https://sc1.checkpoint.com/documents/Jumbo_HFA/R80.40/Default.htm) starting from Take 198

If you choose not to upgrade, [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, collect these files:

1. [CPinfo](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk92739) file from the Management Server involved in the case.
2. [CPinfo](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk92739) file from the Security Gateway / each Cluster Member 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.