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Madhu2ram's avatar
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Feb 26, 2024

modifying DNS question to add client ip to the DNS:: edns0 options

I have a requirement to modify the incoming DNS request to show client IP address in ENDS option 65523. This is in addition to EDNS Client Subnet option, which we already have enabled through DNS profiles.
I am trying achieve to that through below irule but I see some argument and syntax errors. could someone help me fix this irule.


  if { [DNS::edns0 exists] } {

  # Get the client's IP address
  set client_ip [IP::client_addr]
  # Convert client IP to hexadecimal
  set hex_client_ip [format "%02x%02x%02x%02x" [lindex [split $client_ip .] 0] [lindex [split $client_ip .] 1] [lindex [split $client_ip .] 2] [lindex [split $client_ip .] 3]]
  # Create a DNS EDNS option with the client's IP in hexadecimal as the value
  DNS::edns option 65523 $hex_client_ip