F5 Whitelisting/ Allowing a specific range of traffic to VS

Create IP type LTM data-group. Define allowed IP/subnet values, and add optional descriptions. You can find data-group creation page at

Local Traffic - iRules - Data-group List

ltm data-group internal datagroup_allowed_ip {
  records {
    100.20.20.0/32 { }
    199.20.20.128/25 { }
  }
  type ip
}

Create an iRule that checks for matches against entries in datagroup_allowed_ip

when CLIENT_ACCEPTED {
  if { [class match [IP::client_addr] eq "datagroup_allowed_ip" ] }{
     Traffic is allowed. Client IP match found in datagroup_allowed_ip
    return
  } else {
     Traffic is dropped. Client IP match not found in datagroup_allowed_ip
    drop
  }
}