FTP Command PORT : Content Modification

Hi,

 

 

I just need some help to create a very simple irule (simple except for me who doesn't know the code). I have created a virtual server to loadbalance a couple of FTP servers.

 

 

And I noticed that I have a problem with the PORT Command, I explain myself with an exemple :

 

 

Client IP = 10.1.1.1

 

BigIP IP = 192.168.1.1

 

FTP Proxy = 192.168.10.1

 

FTP.Debian = 193.219.61.67

 

 

Everything is OK until the PASV request (Yes, I'm in a passive mode but that's not important).

 

So The PASV request is made from the Client IP to the BigIP which forward to the FTP Proxy.

 

 

The FTP proxy answers to the BigIP "Response: 227 Entering Passive mode (192,168,10,1,199,156)". The BigIP forwards the response to the client.

 

 

Problem is that the FW between the Client IP and the BigIP/Proxy blocks this PORT Command (I understand that Entering passive mode is the PORT FTP Command for FTP passive mode). The Inspection service detects a difference between the flow (10.1.1.1-> 192.168.1.1) and the content of the Entering passive mode command.

 

 

So I would like to know how to replace the IP Address of the FTP Proxy by the BigIP Address in the Entering passive mode command.

 

Ex :

 

Response from the FTP Proxy "Response: 227 Entering Passive mode (192,168,10,1,199,156)"

 

Would become

 

"Response: 227 Entering Passive mode (192,168,1,1,199,156)" from the bigIP to the Client.

 

 

Thank you for your help and excuse my poor english !

 

 

Julien