When I worked at Silicon Graphics, I wrote some network testing software (in PERL!) for a scalable HPC system called the Altix ICE.

It had 2 ethernet networks, an admin network, for communication with nodes on the top of each rack (ToR nodes), and a local to rack network, connecting the compute blades within the rack. The two networks were not connected. Moving between networks, required ssh'ing from the admin node through the ToR node of each rack to the blades.

The challenge was, I could not install additional libraries beyond the systems standard PERL installation, and I had to find a way to relay messages across the 2 networks. So I used netcat, a simple command line multitool, to relay messages between the admin and the local rack network. A fun solution, if not a total hack.

I don't see much netcat'ing as a drop in solution in the wild these days, which is probably a good thing. But I enjoy thinking about the small, functionally solid tools which can make large impact under tight constrains. Netcat is a rather feature rich tool, and its minimalism inspired my personal research project, Udon. But I will leave discussing Udon for another post.