Basic configuration for a new Raspbian installation on RaspberryPi

raspberrypi_setup.sh

#!/bin/bash/

# Basic configuration for a new Raspbian installation on RaspberryPi


# Updates:
sudo apt update
sudo apt -y full-upgrade

# 1. SECURITY: ------------------------------------------

touch $HOME/.ssh/authorized_keys
# Manually paste your RSA public key for SSH login to authorized_keys
#--------------

# Fail2ban to prevent bruteforce attacks:
sudo apt -y install fail2ban
sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local
#--------------

# Adjust 010_$USER-nopasswd -> make password required for sudo->  change NOPASSWD to PASSWD:
## /etc/sudoers.d/010_$USER-nopasswd
sudo sed 's/NOPASSWD/PASSWD/' 010_$USER-nopasswd > temp.txt
sudo mv -f temp.txt /etc/sudoers.d/010_$USER-nopasswd

#-----------------
# Enable SSH:
sudo systemctl enable ssh
sudo systemctl start ssh

# Adjust sshd_config to disable password logins :
## change entries in file (/etc/ssh/sshd_config):
### ChallengeResponseAuthentication no
### PasswordAuthentication no
### UsePAM no
### Port: 1312
sudo sed -e 's/#\?\(ChallengeResponseAuthentication\s*\).*$/\1 no/' -e 's/#\?\(PasswordAuthentication\s*\).*$/\1 no/' -e 's/#\?\(UsePAM\s*\).*$/\1 no/' -e 's/#\?\(Port\s*\).*$/\1 1312/' /etc/ssh/sshd_config > temp.txt
sudo mv -f temp.txt sshd_config

# Restart
sudo service ssh reload

#---------------------

# 2. DUCK DNS: ---------------------------------------------

# create folder with url for duckdns
mkdir $HOME/duckdns
cd $HOME/duckdns
# TODO: replace this example-url
echo "url="https://www.duckdns.org/update?domains=exampledomain&token=a7c4d0ad-114e-40ef-ba1d-d217904a50f2&ip=" | curl -k -o ~/duckdns/duck.log -K -" >> duck.sh
chmod 700 duck.sh

# For first crontab execution
echo 1 | select-editor
# executes crontab in the background
crontab -e &

# Add crontab for duckdns update:
CRON_ADD="*/5 * * * * ~/duckdns/duck.sh >/dev/null 2>&1"
CRON=$(crontab -u $USER -l)
# modify crontab
printf "$CRON\n$CRON_ADD\n" | crontab -u $USER -

sudo service cron start