Mac has problems talking to the old Solaris: symptom:
daniel@DanielMacKay-MacBook ~ % ssh daniel@192.168.2.20
Unable to negotiate with 192.168.2.20 port 22: no matching key exchange method found. Their offer: gss-group1-sha1-toWM5Slw5Ew8Mqkay+al2g==,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
You can edit the Mac ssh config file, but it'll revert next upgrade. Or you can use:
ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 -c 3des-cbc daniel@192.168.2.20