How to SSH to Mac OS X 10.3 (Panther)

 When trying to SSH to an old server, running Panther, from a more modern system, you can get a message like

$ ssh 192.168.0.13
Unable to negotiate with 192.168.0.13 port 22: no matching key exchange method found. Their offer: diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1

Work around it to manually specify the cipher with the “-c” option. You will also probably need to specify the KexAlgorithm

$  ssh -c aes128-cbc -oKexAlgorithms=+diffie-hellman-group1-sha1 192.168.0.13

The authenticity of host '192.168.0.13 (192.168.0.13)' can't be established.

RSA key fingerprint is SHA256:/cjy098VDGhKRFgj2irwEDqMeFpq4CzBz4Hbw2YsBv0.

Are you sure you want to continue connecting (yes/no/[fingerprint])? yes

Warning: Permanently added '192.168.0.13' (RSA) to the list of known hosts.

afberendsen@192.168.0.13's password:

Last login: Fri Jan 22 22:02:08 2021

Welcome to Darwin!

HG000013:~ afberendsen$