As per RFC 2460, section 8.1, UDP packets over IPv6 *must* have a
non-zero checksum. Currently tcpdump ignores this and will print
"udp sum ok". Maybe the author didn't understand how the Internet
checksum works and thought the checksum calculation would catch
This bug and the fix should be reported upstream, but that requires
registration and whatnot.
$ tcpdump -nvr zerocksum.pcap
An example zerocksum.pcap file is attached.
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Status: In Progress Changed: (is less than) 2014-06-01
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