Can't Create SSH Connections with El Capitan

Problem

After updating a Mac to El Capitan, you can't create a SSH connection from Java to your machine.

Cause

El Capitan changes which encryption protocols it agrees with out of the box to secure against future bugs like Heartbleed. The Java library Datameer uses doesn't match with El Capitan when authenticating. 

Solution

1. Add the following line to sshd_config:

KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1

2. Restart SSH using the following command:

sudo launchctl stop com.openssh.sshd