> Source: [sk184158](https://support.checkpoint.com/results/sk/sk184158)

# sk184158 - Manual NAT Service Port Translation Fails When Anti-Spam Blade Is Enabled on an R81.20 Quantum Security Gateway 

| Property | Value |
|----------|-------|
| Solution ID | sk184158 |
| Date Created | 2025-10-20 |
| Last Modified | 2025-10-21 |
| Technical Level | General |
| Products | Security Gateway |
| Versions | R81.20 |
| OS | Gaia |
| Platform | 5000 |

## Symptoms

- * Manual Network Address Translation (NAT) rules that perform service port translation (for example, translating SMTP port 25 to 465) fail to work as expected.

* The traffic is correctly NATed for IP addresses, but service port translation does not occur.

* When the Anti-Spam Blade is enabled, NAT service port translation fails. Disabling the Anti-Spam Blade allows the translation to work as expected.

* Adding Anti-Spam exceptions temporarily resolves the issue.

## Cause

This issue occurs when a manual NAT rule performs service port translation (for example, SMTP port 25 to 465) and the same traffic is also inspected by the Anti-Spam Blade.

Due to an internal conflict between the NAT and Anti-Spam modules, the NAT engine translates the IP address but does not translate the service port.

## Solution

[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 it.  
For faster resolution and verification, collect these files:

1. [CPinfo](https://support.checkpoint.com/results/sk/sk92739) file from the Management Server involved in the case.
2. [CPinfo](https://support.checkpoint.com/results/sk/sk92739) file from the Security Gateway / each Cluster Member / Security Group involved in the case.

**Hotfix installation instructions:**   
Refer to [sk168597 - How to install a Hotfix](https://support.checkpoint.com/results/sk/sk168597).

**Important** : After installing the Hotfix, set the following kernel parameter:  
`fw ctl set -f int fwx_fold_nat_dport 1`  

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