How Passive FTP is filtered in Palo Alto

[yadsingh]

Hi Guys, 

I know application FTP covers both Passive and Active FTP. However, my question is how it filters the traffic. I mean how a server Intiating a connection to the client will be filtered and allowed. Can anyone help. 

[BenjAudy.MTL · Accepted solution]

Hi,

The firewall create predict sessions. You can read about it here:

https://live.paloaltonetworks.com/t5/Learning-Articles/Palo-Alto-Networks-Firewall-Session-Overview/...

Benjamin

[tsrivastav]

#Firewall works on the concept of inspection.
#Connection request will be sent on port 21 , return packet will contain the DATA ports ( for example 3453  )

Firewall inspects this session and  since it a past of a existing session,

#Firewall Opens a by-default pin hole for the data port  ( as it already inspected the S2C packet ) and the traffic going on the data port are allowed. 

[tsrivastav]

So if your question was how the firewall allows the traffic going on the data ports from Client to server 

then Inspection of the FTP application is the answer

also predict session plays an imp. role in the same