Help with X-Forwarded-For iRule

I would not enable the acceptance of XFF, for it can be faked. You should only trust the IP address that initiated the connection as the client address. As such, you can try the irule below.

when HTTP_REQUEST_RELEASE {
    log local0. "Orig XFF: [HTTP::header values "X-Forwarded-For"]"
    HTTP::header remove "X-Forwarded-For"
    HTTP::header insert "X-Forwarded-For" [getfield [IP::client_addr] % 1],[getfield [IP::local_addr] % 1]
    log local0. "New XFF: [HTTP::header value "X-Forwarded-For"]"
}

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