The idea that the military had deployed anything like "the internet" back in the 50's or sixties is pure hokum. The military was funding some very early research which was being carried out by private and public institutions at the time, but there were no secret military "internet" installations. In 1969, ARPANET allowed researchers in MIT to use a semi-trailer sized computer which cost 100's of thousands or more to talk to a few other similarly situated computers.
One of the first ARPANET transmissions was described like this:
"We set up a telephone connection between us and the guys at SRI...," Kleinrock ... said in an interview: "We typed the L and we asked on the phone,
"Do you see the L?"
"Yes, we see the L," came the response.
"We typed the O, and we asked, "Do you see the O."
"Yes, we see the O."
"Then we typed the G, and the system crashed"...
If anyone is interested here's a short history on the beginnings of the internet. History of the Internet & World Wide Web:
All that trouble “sending” a few letters. I wonder how the teletype worked?