diff --git a/doc/API/ARP.md b/doc/API/ARP.md
index 7b98379cee..c842f4e8b7 100644
--- a/doc/API/ARP.md
+++ b/doc/API/ARP.md
@@ -9,6 +9,7 @@ Route: `/api/v0/resources/ip/arp/:query`
 
 Query can be:
 - An IP address
+- A MAC address
 - A CIDR network (192.168.1.0/24)
 - `all` and set ?device=_hostname_ (or device id)