Is there ssh for MSX?
Currently I'm using Sony MSX2 with GR8NET cartridge for retro gaming and recreational software development (BASIC and Fusion-C). With GL.iNet GL-SFT1200 Wi-Fi router I have access from MSX to all my network devices via Wi-Fi and planned to ssh to Raspberry Pi to perform routine management tasks in terminal. Imagine my surprise when Google search did not return any meaningful results for "ssh for msx2" search. So:
1) Should I try Lycos.com instead?
2) How hard would be implement simple ssh client for MSX using C?
MSX itself, alone, can't handle TSL/SSL or SSH. Any connection would time out before MSX would even think of finishing the calculations...
Currently we have two UNAPI solutions that allows TLS/SSL, one is made by Konamiman / Nestor Soriano and requires you to use a Linux computer (or a Pi) connected to the MSX to tunnel TLS/SSL through it. The other is the Wi-Fi solution I've implemented for SM-X / SX2 and that KdL has designed and made available an adapter for OCM/Zemmix Neo and its CLONES like SX1.
There is currently no solution to use SSH in MSX, since it is a different protocol that doesn't use TLS/SSL. In the case of my solution, Victor Trucco chose an ESP-01 module that has only 1MB of flash memory, and the ESP8266 firmware for that solution is already occupying 95% of the free space and still allowing firmware updates (in fact I've designed a hack, I'm using 148% and still allow safe firmware update but 256KB devoted to SSL certificates needs to be resent whenever you update the firmware), so I had to choose between SSL/TLS or SSH and I've chosen SSL because UNAPI already specified it and I think it is more useful (https connections are almost mandatory nowadays, and can be used for other stuff like telnet or ftp over ssl, but a client for that still needs to be implemented).
But, there is an easy way to SSL, you can use my telnet client (available at msxhub) and it has almost full ansi 16 colors support (except for blink) and works really nice connecting to Linux machines, so you can telnet to a PI that has telnet restricted to your local network and then from the Pi ssh to anywhere in your network or in the internet safely.
There are no plans as far as I know, from anyone, to do an adapter and software that makes it possible to directly ssh from the msx, so that is the only way to get it for now and in the foreseeable future.
Hope that info helps you 
I think I have nothing to add to what has been said, except for this picture of my MSX telneting into a Raspberry Pi. As it is already stated, do this only on a trusted, well-controlled network.
