I've got several client computers (i.e. laptops, desktops, etc.), and I connect to several server machines that I manage, and I log into them all via SSH. I can imagine several schemes of managing ssh keys that would make sense, and I'm curious about what others do.
Option 1: One global public/private keypair.
I would generate one public/private keypair, and put the private key on every client machine, and the public key on every server machine.
Option 2: One keypair per server machine.
I would generate one keypair on each server machine, and put each private key on my client machines.
Option 3: One keypair per client machine.
Each client machine would have a unique private key, and each server machine would have the public keys for every client machine that I'd like to connect from.
Option 4: One keypair per client/server pair
Which of these is best? Are there other options? What criteria to you use for evaluating the right configuration?