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[TN#011] Capturing AFP network traffic

Author

Ralph Böhme

Published on

August 29, 2012

GUI Tool for packet capturing

You can use a nice program called CocoaPacketAnalyzer in order to capture AFP network traffic.

Step 1

Download and extract the program from the above link.

Step 2

Start it.

Step 3

Press “Capturing”.

Press Capturing

Step 4

In the dialog window that opens, choose the active network interface. The first time, you may be asked to scan for interfaces.

Choose network interface

Step 5

Enter “port 548” as the filter expression.

Enter filter expression

Step 6

When ready to do the actual trace, press “start.” When done with the trace, press “stop.” Minimize activities on the AFP volume and perform only necessary actions.

Step 7

Finally, choose “Save” from the “File” menu to save the trace to a file.

Editor’s note: Use the application that you download from the above link, rather than the one available in the App Store. The latter can only analyze pcap logs, and not capture them.

Using tcpdump with a ringbuffer

Another useful thing only available in Terminal with tcpdump is using a ringbuffer:

# tcpdump -s 0 -w afp.pcap -C 10 -W 2 port 548

This limits the captured data to two capture files (-W 2) with a size of 10 MB each (-C 10). This way for large amount of AFP traffic, only the last 10-20 MB will be saved and available for analysis.