Seems to me like 715 MB is about right, at least it's not off by a factor of 10.
There's no way you could fit six DNS queries and a couple of NTP queries into 138 bytes.
As pointed out by jlgaddis, based on the numbers in the article given for the size of DNS & NTP requests and responses, seems like the author meant 1380 bytes.
My third edit included a bit more on this - I'm closer to 600 bytes total than 1380. A few of them are sitting at closer to 80 bytes for a request+response for DNS, etc. With a quick while loop and tcpdump, I'm seeing the number as being off by about 2x from my testing.
My DNS numbers are all basically half his - all of my requests are sub 40 bytes, responses are all sub 80, some are sub 60. My NTP query and response packets are pretty close, though - sitting around 80 bytes for request and response.
Can you take a look at the edit and comment on where your numbers differ exactly? I tried to be as accurate as possible. I used the busybox_NTPD from https://busybox.net/downloads/binaries/
There's no way you could fit six DNS queries and a couple of NTP queries into 138 bytes.
As pointed out by jlgaddis, based on the numbers in the article given for the size of DNS & NTP requests and responses, seems like the author meant 1380 bytes.
That gets you about 715 MB (or about 682 MiB).