Client IP visibility issue at Remote Server

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Client IP visibility issue at Remote Server

L3 Networker

Hi Team,

Below is possible in paloalto side?


Note: there is no proxy in between client and paloalto


Problem description :

The clients behind PA firewall connecting to AWS NLB then connecting to our AWS web servers(https://  Now we are not able to see the actual client ip address in the AWS Web server.  To resolve this issue AWS team suggested to insert XXF header in the client traffic. Can we achieve this in PA?


As per AWS :

" The internal ALB appends the NLB’s private IP address in the X-Forwarded-For header before sending to a request to the backend targets. Therefore, if the requests from the clients contain X-Forwarded-For header, the backend targets will see the clients’ actual IP addresses along with the private IP address of the NLB in the X-Forwarded-For header. Otherwise, the backend targets will only see the NLB’s private IP address in the X-Forwarded-For header. "


Can anyone help me here?




Sethupathi M


L4 Transporter

@Sethupathi As the file does not act as proxy for the traffic, it is not able to modify the HTTP header and insert "x-forwarded-for"


Check the config on the load balancer. some have the option to let you see the source IP after the LB. However this is a common issue with using LB's.


Sorry its not a solution :(.



Cyber Elite
Cyber Elite

@Sethupathi i agree with @OtakarKlier , this can be control on LB itself. There are two options on LB as follows


1. Without SNAT. here client actual IP address is send to server but in this case mostly asymmetric routing issues are observed as most of the times, application server default gateway is not set to LB.


2. To avoid above issue, SNAT is enabled which actually NATs client IP address with one of the LB IP while sending request to application server.

If you want to see actual client IP on server side with SNAT enabled, you need to enable X-forwarder-for setting on LB side which actually adds client IP under header while sending request to web server.


hope it helps!



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