AWALL - Alpine firewall, rule that accept traffic from certain IP

Question

I need a rule that permits a specific traffic from determinate IP. I tried this, but it doesn't work.

{
  "src": ["$FDFARM", "$FARM"],  
  "in": "internet",
  "out": "_fw",
  "service": "APIDOCKER",
  "action": "accept",
  "conn-limit": { "count": 3, "interval": 60 }
}

Any idea?