> Source: [sk180825](https://support.checkpoint.com/results/sk/sk180825)

# sk180825 - TCP source port 30500 and 34500 traffic getting port changed to 4500 when VPN blade enabled

| Property | Value |
|----------|-------|
| Solution ID | sk180825 |
| Date Created | 2023-04-04 |
| Last Modified | 2023-04-04 |
| Technical Level | General |
| Products | Security Gateway |
| Versions | R81.20, R81.10 (EOS) |
| OS | Gaia |

## Symptoms

- * Security GAteway accepts incoming traffic from source port 34500 or 34500 but drops it after port change to either 500 or 4500.

* Kernel debug shows :  

  `@... DATE TIME PID;[vs_0];[tid_0];[fw4_0];vpnk_multik_forward (out): src 172.19.112.132:34500 ;`  
  `@... DATE TIME PID;[vs_0];[tid_0];[fw4_0];vpnk_multik_forward (out): dst 172.22.64.50:5487, IPP 6;`  
  `@... DATE TIME PID;[vs_0];[tid_0];[fw4_0];vpnk_multik_forward (out): multicore VPN enabled;`  
  `@... DATE TIME PID;[vs_0];[tid_0];[fw4_0];vpnk_multik_forward_vpnxl: restore iked port, if relevant;`  
  `@... DATE TIME PID;[vs_0];[tid_0];[fw4_0];calc_handling_daemon_index: returning 'iked' index '0' for 172.22.64.50;`  
  `@... DATE TIME PID;[vs_0];[tid_0];[fw4_0];get_iked_virtual_port: this is a virtual packet of iked: 0. virtual port: 34500, orig port: 4500;`

## Cause

TCP 4500 is getting auto-translated

## 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://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).

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