I'm sure I asked this some time ago (i.e. some years ago!) and used the recommended program to check if all my ethernet links were actually running at the spped they were supposedly capable of.
I want to check again and I can't find/remember the program to use.
I have found ethtool which tells me the speed of a specific port on the system where it is running but I seem to remember there was a tool which somehow checked both ends of a link and told me that the remote end speed as well. That's the remote end at the other side of routers, switches etc.
Maybe I'm imagining it as I don't really see *how* such a tool could work.
The basic requirement at the moment is that I want to check that the link to my backup system in the garage is still running at full Gigabit speed. The remote system is fairly limited and, although I have ssh access to it, I can't find ethtool or an equivalent for it.