diff --git a/unifi/firewall_policy.go b/unifi/firewall_policy.go
index af01b20..557e8d8 100644
--- a/unifi/firewall_policy.go
+++ b/unifi/firewall_policy.go
@@ -29,7 +29,7 @@ type FirewallSource struct {
 		MatchOppositePorts    bool     `json:"match_opposite_ports"`
 		MatchingTarget        string   `json:"matching_target"`
 		MatchingTargetType    string   `json:"matching_target_type"`
-		NetworkIDs            []string `json:"network_ids"`
+		NetworkIDs            []string `json:"network_ids,omitempty"`
 		Port                  string   `json:"port"`
 		PortMatchingType      string   `json:"port_matching_type"`
 		ZoneID                string   `json:"zone_id"`