SNAT pool and persistence

  
  when CLIENT_ACCEPTED {  
      Create some snat name to IP variables  
     set snat0_ip 1.1.1.1  
     set snat1_ip 2.2.2.2  
     set snat2_ip 3.3.3.3  
     set snat3_ip 4.4.4.4  
     set snat4_ip 5.5.5.5  
    
      Test with a dummy client IP address  
     set client_ip "10.11.12.13"  
     log local0. "\$client_ip: $client_ip"  
    
      Scan the dummy IP address for each octet  
     scan $client_ip {%[0-9].%[0-9].%[0-9].%[0-9]} a b c d  
     log local0. "result: \[expr {$c % 5}\]: [expr {$c % 5}]"  
    
      Use modulus 5 on the third octet  
     log local0. "Snat command: snat [set "snat[expr {$c % 5}]_ip"]"  
    
      Apply the SNAT IP to this connection  
     snat [set "snat[expr {$c % 5}]_ip"]  
  }  
  

  
  when CLIENT_ACCEPTED {  
    
      Use a local array to configure the 5 SNAT addresses  
     set snat_ips(0) 1.1.1.1  
     set snat_ips(1) 2.2.2.2  
     set snat_ips(2) 3.3.3.3  
     set snat_ips(3) 4.4.4.4  
     set snat_ips(4) 5.5.5.5  
    
      Use getfield to parse the third octet from the client IP address  
      Get the modulus of the third octet against the number of the SNAT IPs in the array  
     set snat_number [expr {[getfield [IP::client_addr] "." 3] % [array size snat_ips]}]  
     log local0. "Client IP: [IP::client_addr], SNAT number $snat_number, SNAT IP: $snat_ips($snat_number)"  
    
      Apply the SNAT  
     snat $snat_ips($snat_number)  
  }