diff --git a/config/voipmonitor.conf b/config/voipmonitor.conf
index 7554996b6..cb16d3f14 100644
--- a/config/voipmonitor.conf
+++ b/config/voipmonitor.conf
@@ -132,6 +132,7 @@ promisc = yes
 # Pcap filter. If you want to sniff only UDP SIP, put here 'udp'. Warning: If you set protocol to 'udp' pcap discards VLAN packets. Maximum size is 2040 chars
 # udp or (vlan and udp) will capture all tagged and untagged UDP packets
 # WARNING - if you need to sniff IPinIP (like mirrored packets from voipmonitor) filter = udp will filter all those packets. In this case just disable filter. 
+# WARNING - this rule "udp or (vlan and udp)" will not capture double VLAN tagged packets 
 
 #filter = udp or (vlan and udp)