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Ruggerfly1
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May 03, 2018

IRULE to Set APM Session variable for X-Forwarded-For

Good Afternoon,

 

I have a Network that connects to a VIP and all addresses are NAT'd behind the same IP. They are using a X-Forwarded-For in the Header. I'd like to set an APM Session Variable "session.custom.xforwardedfor" and then use something in APM like an Empty Box and regexpr to match a few client IP's.

 

Suggestions?

 

thanks!

 

  • You can get the XFF header in ACCESS_SESSION_STARTED event, and evaluate the value in the irule.

    when ACCESS_SESSION_STARTED {
        set xforwardedfor [HTTP::header values {X-Forwarded-For}]
        ACCESS::session data set session.custom.xforwardedfor $xforwardedfor
        switch $xforwardedfor {
            "1.1.1.1" -
            "2.2.2.2" -
            "3.3.3.3" {
                ACCESS::session data set session.custom.xff_known_ip 1
            }
            default {
                ACCESS::session data set session.custom.xff_known_ip 0
            }
        }
    }
    

    Then check the value in the empty box

    expr { [mcget {session.custom.xff_known_ip}] == 1 }
    
  • get close the irule saves, but no APM session variable written with this.

     

    when HTTP_REQUEST { set xforwardedfor "[HTTP::header values {X-Forwarded-For}]" log local0. "$xforwardedfor" ACCESS::session data set session.custom.xforwardedfor $xforwardedfor }

     

  • this writes the variable:

     

    when HTTP_REQUEST { set xforwardedfor "[HTTP::header values {X-Forwarded-For}]" log local0. "$xforwardedfor" } when ACCESS_SESSION_STARTED { ACCESS::session data set session.custom.xforwardedfor $xforwardedfor }

     

    now phase 2

     

  • Finished - perhaps not optimised but working:

     

    APM policy - Empty Box - used this: expr { [string tolower [mcget {session.custom.xforwardedfor}]] contains "1.1.1.1" || [string tolower [mcget {session.custom.xforwardedfor}]] contains "2.2.2.2" }