As recently as a 2001, it was not uncommon to log in to a remote Unix system using telnet.
Telnet is just above netcat in protocol sophistication, which means that passwords were sent in the clear.
As wifi proliferated, telnet went from security nuissance to security disaster.
As an undergrad, I remember running ethereal (now wireshark) in the school commons area, snagging about a dozen root passwords in an hour.
SSH, which encrypts and authenticates connections, had been in development since 1995, but it seeme