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VoIP Call Simulation & Analysis
Frequently Asked Questions

  1. When I use packetScan to capture packets, I see only packets to and from my machine, or I'm not seeing all the traffic I'm expecting to see from or to the machine I'm trying to monitor.
  2. I don't see SIP packets even when I was expecting to capture it.
  3. PacketScan™ does not show outbound Traffic.


When I use packetScan to capture packets, I see only packets to and from my machine, or I'm not seeing all the traffic I'm expecting to see from or to the machine I'm trying to monitor.

This might be because the interface on which you're capturing is plugged into a switch; on a switched network, unicast traffic between two ports will not necessarily appear on other ports - only broadcast and multicast traffic will be sent to all ports. Note that even if your machine is plugged into a hub, the "hub" may be a switched hub, in which case you're still on a switched network.

Note also that on the Linksys Web site, they say that their auto-sensing hubs "broadcast the 10Mb packets to the port that operate at 10Mb only and broadcast the 100Mb packets to the ports that operate at 100Mb only", which would indicate that if you sniff on a 10Mb port, you will not see traffic coming sent to a 100Mb port, and vice versa. This problem has also been reported for Netgear dual-speed hubs, and may exist for other "auto-sensing" or "dual-speed" hubs.

Some switches have the ability to replicate all traffic on all ports to a single port so that you can plug your analyzer into that single port to sniff all traffic. You would have to check the documentation for the switch to see if this is possible and, if so, to see how to do this.


I don't see SIP packets even when I was expecting to capture it.

One possible reason is the Capture Filter is not configured properly. Select menu item "Capture"->"Capture Filters..." and for SIP, select "Filter All SIP data". This will activate Port number 5060 as default SIP. If you happened to know that your equipment is not using standard port# 5060 for SIP, then you would have to enter it into the "SIP Port" entries.


PacketScan™ captures only incoming traffic, but not outgoing traffic for the selected Network Adapter.

One possible reason could be the selection of DNE LightWeight Filter option in the Network Adapter Properties, uncheck the DNE LightWeight Filter option and restart the machine to see the changes.

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