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Forum Discussion

JustCooLpOOLe's avatar
JustCooLpOOLe
Icon for Cirrocumulus rankCirrocumulus
Jun 09, 2017

Multiple IPs coming in the client_addr and remote_addr header fields

I'm trying to write an iRule that only places a single IP address in the X-FORWARDED-FOR header. I am using the one below but we are seeing rare cases where the client_addr or remote_addr fields ar...
application delivery
iRules
LTM
dragonflymr's avatar
dragonflymr
Icon for Cirrostratus rankCirrostratus
Jun 09, 2017

Hi,

First of all there is no way that [IP::remote_addr] can return multiple IPs - just not possible with TCP.

I guess your conclusion is based on the fact that request arriving to the backend host is still containing multiple XFF headers.

Reason is simple, if original request contains multiple XFF headers then HTTP::header replace is just replacing value/s in last XFF header.

Use combination of:

HTTP::header remove X-Forwarded-For

followed by:

HTTP::header insert X-Forwarded-For [IP::remote_addr]

Piotr