Maybe obvious to others, but on MacOS I had to `brew install telnet` since it was not installed by default and then `telnet flame.ucc.gu.uwa.edu.au 4242`.

In the 90's I thought it would make for a wild scene in a (cyberpunk?) story where the protagonist agrees to meet up with a possible informant in a MUD bar. The two apparently idly chatting possibly state secrets while fights between fighters and magic users break out around them.