New Server (Ubuntu Linux)

After installing a fresh Ubuntu Server from an ISO (or spinning up a cloud VM), you need to get it securely on the network before you can actually start using it.

1. Set a Static IP Address

Ubuntu uses netplan for network configuration.

1. Open the Netplan config file (the filename may vary, usually starts with 50- or 00-):

   sudo nano /etc/netplan/00-installer-config.yaml
   

2. Modify it to use a static IP (assuming your interface is eth0):

   network:
     ethernets:
       eth0:
         addresses:
           - 10.10.10.25/24
         routes:
           - to: default
             via: 10.10.10.1
         nameservers:
           addresses: [8.8.8.8, 1.1.1.1]
     version: 2
   

3. Apply the changes:

   sudo netplan apply
   

2. Secure SSH Access

Never rely on passwords for SSH. You should set up SSH keys.

From your local laptop, generate a key and copy it to the server:

# Generate a key (if you don't already have one)
ssh-keygen -t ed25519

# Copy it to the new server
ssh-copy-id username@10.10.10.25

Now, disable password authentication on the server:

sudo nano /etc/ssh/sshd_config

Find the line PasswordAuthentication yes and change it to no. Restart SSH:

sudo systemctl restart ssh

3. Update Packages

Finally, ensure the system is fully patched and secure:

sudo apt update && sudo apt upgrade -y