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René_Posthumus's avatar
René_Posthumus
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Dec 22, 2020

iRules: Putting the source port of a client in a HTTP header to a backend for logging

Hi everybody,

I'm up to a challenge. We need to be able to record the source IP and port of a client to do some extra logging, but i'm missing something, or maybe it's not possible at all. I got this far that i'm able to log the source port to the local log, but the variable it is stored in, looks unavailable to the HTTP_REQUEST event but only to the SERVER_CONNECTED event. Is there any way to accomplish the thing i need using iRules?

The current rule:

when SERVER_CONNECTED {
  set clientsourceport [TCP::client_port]
  set curtime [clock seconds]
  set formattedtime [clock format $curtime -format {%T} ]
  set client_ip [IP::client_addr]
  
  log local0. "Connection on $formattedtime from $client_ip with source port $clientsourceport."
  }
  
when HTTP_REQUEST {
  HTTP::header insert X-Client-Source-Port "$clientsourceport"
  log local0. "Request headers [HTTP::request]"
}

Results in  <HTTP_REQUEST> - can't read "clientsourceport": no such variable   while executing "HTTP::header insert X-Client-Source-Port "$clientsourceport""

Does anyone have a solution to this?

Regards,

René

application delivery
iRules

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  • René_Posthumus's avatar
    René_Posthumus
    Icon for Altostratus rankAltostratus
    Dec 22, 2020

    Figured out myself using some other posts, i had to use CLIENT_ACCEPTED instead of SERVER_CONNECTED event. Now it works fine! 😀

     

    So to be complete, this is the code:

     

    when CLIENT_ACCEPTED {
  set clientsourceport [TCP::client_port]
  set curtime [clock seconds]
  set formattedtime [clock format $curtime -format {%T} ]
  set client_ip [IP::client_addr]
  
  log local0. "Connection on $formattedtime from $client_ip with source port $clientsourceport."
  }
  
when HTTP_REQUEST {
  HTTP::header insert X-Client-Source-Port "$clientsourceport"
  log local0. "Request headers [HTTP::request]"
}