Problem
ssh root@192.168.2.203
Unable to negotiate with 192.168.2.203 port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1
Solution
ssh root@192.168.2.203 -oKexAlgorithms=+diffie-hellman-group1-sha1
Ou ssh -c cyphername root@192.168.2.203