I encountered many corrupted downloads recently. Sometimes compressed files wouldn’t open or checksums would not match. Sometimes images on Websites would just be grey (or a wild mix of colour) after a few lines of correct pixels.
So I decided to take a deeper look at it and ran Memtest86+ (5.0.1) for 24 hours with no errors.
To rule out my Internet connection I set up another computer as a simple apache http file host. I created some test files of ~100 MiB each but after transmission the checksums would not match. Not even the checksums of the whole set downloaded twice.
When I ran Wireshark during transmission I came across several “Dup ACK” packets and “Spurious Retransmission” Packets during the file transfer between me and the apache server.
The Checksum Comparison of two different downloads of the same set of files can be found in picture
and one example of the “Dup ACK” and “Spurious Retransmission” between file server and my machine is:
Does anyone know likely causes for this behavior?