Disable weak SSH encryption algorithms

Disable weak SSH encryption algorithms Ubuntu, CentOS

1. Open the /etc/ssh/sshd_config any in a text editor;

sudo nano /etc/sshd/sshd_config

2. Find 2 lines Ciphers….. and MACs……;

3. Incert the next string between these lines:

KexAlgorithms ecdh-sha-nistp384

4. It works by simple principle if you don’t use KexAlgorithms in sshd_config – the system use default values and if you write KexAlgorithms in sshd_config – the system use only that you specified;

5. Restart sshd and check its status:

sudo systemctl restart sshd
sudo systemctl status sshd

NOTE: Works in Ubuntu and only CentOS 7, not work in CentOS 8