MacOS No Longer Allowing You to SSH to Older Devices?

If you are you seeing error messages like

Unable to negotiate with "xxx" port "xxx": no matching cipher found. Their offer: aes128-cbc, 3des-cbc, blowfish-cbc, cast128-cbc, arcfour, aes192-cbc, aes256-cbc, rijndael-cbc @ serve<em>r

You can either upgrade the SSH server to support these newer, more secure, algorithms or you can enable these older ciphers on your Mac by performing the following:

sudo nano /etc/ssh/ssh_config

Find the section beginning with and remove the leading # to uncomment these disabled ciphers

Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc

Another option is to edit the per user ssh configuration file like this

nano ~/.ssh/config

Host *
SendEnv LANG LC_*
Ciphers +aes256-cbc