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How does the Fortigate firewall deal with an XFF header inserted

Hi; I would like to have Fortigate insert an X-Forwarded-For header by using the "Preserve Client IP" option available with a load balancing virtual server. My question is: If there is an upstream device that inserted the XFF header before the Fortigate, does the fortigate add a second value to the first. So:


X-Forwarded-For: value1 inserted by upstream device, value2 inserted by Fortigate


Or does it add a second occurance of the XFF header, like:


X-Forwarded-For: value1 by upstream device

X-Forwarded-For: value2 by Fortigate Kindly Wasfi

Esteemed Contributor III

I believe it's appends to the existing XFF not add 2 XFF headers. if you add 2 XFF headers line I seen strage things where only the last one is picked up or something like that.


So it  should looked like "X-Forwarded-For: x.x.x.x, y.y.y.y"



Ken Felix




PCNSE NSE StrongSwan
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