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Properly using tcpdump with Wireshark to avoid stanag4607 errors

Posted November 09, 2015 by shaun

Years ago it was possible to do a packet capture on a Linux machine by redirecting the output of tcpdump to a file, and Ethereal (ah, memories) would open it up. Somewhere along the way, Wireshark started choking on these files. Every now and then I still forget and try to do something like this:

    tcpdump -nn -vv -S -X -s0 -i eth0 port 53 > /tmp/dns.cap

That captures a bunch of packets in human-readable form, but Wireshark refuses to open the file. It gives an error along the lines of:

    The capture file appears to be damaged or corrupt.
    (stanag4607: File has 976238138d-byte packet, bigger than maximum of 262144)

If you find yourself looking at this error, make sure to use the -w flag to tcpdump instead of redirecting stdout:

    tcpdump -nn -vv -S -X -s0 -i eth0 port 53 -w /tmp/dns.cap

This generates a binary pcap file that Wireshark happily opens up.

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