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Introduction |
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Using the Program |
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VoIP Analysis |
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Advanced Topics |
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Information |
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Capturing Loopback Traffic
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CommView allows you to capture traffic on the loopback interface. To start monitoring the loopback interface, select it from the drop-down list in the toolbar.
Loopback packets are the packets sent/received within the same computer, i.e. self-addressed packets. Typically, there is virtually no loopback traffic on the standard PC. However, loopback traffic is widely used by software developers for debugging network-related applications. Therefore, CommView's loopback capturing functionality is targeted primarily at this user group.
When you capture loopback traffic, the packets look exactly as any other network packets, except that the checksums are not computed. Please pay attention to the following peculiarities when capturing loopback traffic:
| · | CommView captures loopback traffic on all of the local IP addresses. This always includes 127.0.0.1/255.0.0.0, but may also include the IP addresses of your Ethernet adapters, e.g. 192.168.0.1.
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| · | ICMP packets cannot be captured. Other IP protocols can (TCP, UDP, etc.).
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| · | Only successfully sent/received packets are captured. For example, if a connection attempt fails because the destination port is closed, you will not see any SYN / RST packets.
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| · | Sessions are silently closed; no FIN packets are captured.
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