debian-seed

A guide to setting up and maintaining a Debian VPS—secure, robust, and production-ready.

Basic Server Configuration
Security Hardening
Web Server Setup
Monitoring
Server Maintenance
Data Backups
Upgrade Process
Bootstraps

1. Basic server configuration

Basic Linux configurations to use in all VPS instances.

System update && upgrade

apt update && apt upgrade

Hostname change

hostnamectl set-hostname "hostname"

Update /etc/hosts

echo "hostname" > /etc/hostname
hostname -F /etc/hostname

Timezone setup

dpkg-reconfigure tzdata
date

New user

adduser "username"

Sudo

apt install sudo
usermod -a -G sudo "username"

Fish

A modern, easy-going, and powerful shell.

sudo apt install fish
sudo chsh -s /usr/bin/fish

Reboot

sudo shutdown -r now

2. Hardening

Basic hardening configurations to use in all VPS instances.

SSH hardening and daemon configuration

On the server:

mkdir -p ~/.ssh/ && sudo chmod -R 700 ~/.ssh/
sudo chmod 700 -R ~/.ssh && chmod 600 ~/.ssh/authorized_keys

On local machine:

scp ~/.ssh/id_rsa.pub username@vpsipaddress:~/.ssh/authorized_keys

File: /etc/ssh/sshd_config

# Authentication reforce
PermitRootLogin no
PasswordAuthentication no

# Listen on only on IPv4
AddressFamily inet

Restart SSH

sudo systemctl restart sshd

Fail2ban

Simple intrusion prevention software.

apt install fail2ban

Configure:

cp /etc/fail2ban/fail2ban.conf /etc/fail2ban/fail2ban.local
cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

Lets configure jail.local with optimized settings:

sudo nano /etc/fail2ban/jail.local

[DEFAULT]
# Base settings with progressive banning
bantime  = 24h        # Initial ban duration
findtime = 15m        # Detection window
maxretry = 2         # Failures allowed before ban

# Progressive ban system for repeat offenders
bantime.increment = true
bantime.multipliers = 1 3 6 12 24 48
bantime.maxtime = 4w
bantime.factor = 1

# Basic security settings
ignoreip = 127.0.0.1/8 ::1
backend = auto
usedns = warn
banaction = iptables-multiport
protocol = tcp
chain = INPUT

[sshd]
enabled = true
port = ssh
filter = sshd
logpath = /var/log/auth.log
maxretry = 2
findtime = 10m
bantime = 48h

[nginx-badhosts]
enabled = true
port = http,https
filter = nginx-badhosts
logpath = /var/log/nginx/error.log
maxretry = 3
findtime = 15m
bantime = 24h

Then create a custom filter for nginx SSL issues:

sudo nano /etc/fail2ban/filter.d/nginx-badhosts.conf

[Definition]
failregex = SSL_do_handshake\(\) failed .* client: <HOST>
ignoreregex =

Adding a verification section:

sudo systemctl restart fail2ban
sudo systemctl status fail2ban
sudo fail2ban-client status
sudo fail2ban-client status sshd
sudo fail2ban-client status nginx-badhosts

Test the nginx filter against logs:

sudo fail2ban-regex /var/log/nginx/error.log /etc/fail2ban/filter.d/nginx-badhosts.conf

Monitor fail2ban activity:

sudo tail -f /var/log/fail2ban.log

Check currently banned IPs:

sudo fail2ban-client get sshd banned
sudo fail2ban-client get nginx-badhosts banned

Crowdsec

Modern, collaborative security engine that works alongside fail2ban.

Installation

# Add Crowdsec repository
curl -s https://packagecloud.io/install/repositories/crowdsec/crowdsec/script.deb.sh | sudo bash

# Install Crowdsec with nginx collection
sudo apt install crowdsec
sudo apt install crowdsec-nginx-bouncer

# Initial setup
sudo cscli hub update
sudo cscli collections install crowdsecurity/nginx
sudo cscli collections install crowdsecurity/linux
sudo cscli collections install crowdsecurity/http-cve

Create parsers configuration:

sudo nano /etc/crowdsec/acquis.yaml

filenames:
  - /var/log/nginx/access.log
  - /var/log/nginx/error.log
labels:
  type: nginx

Configure Nginx Bouncer:

sudo nano /etc/crowdsec/bouncers/crowdsec-nginx-bouncer.conf

api_key: # Will be automatically populated
ban_time: 1h
ban_mode: http-403
include_scenarios:
  - crowdsecurity/http-probing
  - crowdsecurity/http-bad-user-agent
  - crowdsecurity/nginx-http-bad-user-agent
  - crowdsecurity/http-crawl-non_statics
  - crowdsecurity/http-path-traversal-probing

Configure Nginx for Crowdsec:

sudo nano /etc/nginx/conf.d/crowdsec_nginx.conf

load_module /usr/lib/nginx/modules/ngx_http_crowdsec_module.so;

http {
    crowdsec_instance {
        path /var/run/crowdsec/crowdsec-nginx-bouncer.sock;
    }
    # ... rest of your http configuration
}

Start Services

# Restart services to apply changes
sudo systemctl restart crowdsec
sudo systemctl restart nginx
sudo systemctl enable crowdsec

# Verify services
sudo systemctl status crowdsec
sudo cscli hub list

Basic Commands

# Check Crowdsec status
sudo cscli metrics

# List current bans
sudo cscli decisions list

# List active scenarios
sudo cscli scenarios list

# List bouncers
sudo cscli bouncers list

# Check real-time logs
sudo journalctl -f -u crowdsec

# Add IP to whitelist
sudo cscli decisions add --ip X.X.X.X --duration 168h --type whitelist

# Remove IP from bans
sudo cscli decisions delete --ip X.X.X.X

Maintenance: daily tasks

# Update hub collections
sudo cscli hub update

# Check for outdated scenarios
sudo cscli scenarios list -o

# Review metrics
sudo cscli metrics

# Review current decisions
sudo cscli decisions list

# Check bouncer status
sudo cscli bouncers list

Maintenance: weekly checks

# Full database cleanup
sudo cscli database cleanup

# Update all collections
sudo cscli collections upgrade

# Check configuration validity
sudo crowdsec -c /etc/crowdsec/config.yaml -t

Integration with fail2ban

Crowdsec can work alongside fail2ban. Configure fail2ban to respect Crowdsec's decisions:

sudo nano /etc/fail2ban/jail.local
```
Add to [DEFAULT] section:
````console
ignoreip = 127.0.0.1/8 ::1 # Add your IPs and Crowdsec's IP range if used
```

### Rootkit protection

Rkhunter and chkrootkit:

```console
sudo apt install rkhunter
sudo rkhunter --propupd
sudo rkhunter --check
sudo apt install chkrootkit

Firewall

Always iptables: Minimal configuration; Easygoing; Effective.

sudo iptables -L
sudo apt install iptables-persistent
sudo nano /etc/iptables/rules.v4

iptables file [ download here ]:

*filter
# Allow all outgoing, but drop incoming and forwarding packets by default
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]

# Custom per-protocol chains
:UDP - [0:0]
:TCP - [0:0]
:ICMP - [0:0]

# Acceptable UDP traffic

# Acceptable TCP traffic
-A TCP -p tcp --dport 80 -j ACCEPT
-A TCP -p tcp --dport 443 -j ACCEPT
-A TCP -p tcp --dport 22 -j ACCEPT

# Acceptable ICMP traffic

# Boilerplate acceptance policy
-A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
-A INPUT -i lo -j ACCEPT

# Drop invalid packets
-A INPUT -m conntrack --ctstate INVALID -j DROP

# Pass traffic to protocol-specific chains
## Only allow new connections (established and related should already be handled)
## For TCP, additionally only allow new SYN packets since that is the only valid
## method for establishing a new TCP connection
-A INPUT -p udp -m conntrack --ctstate NEW -j UDP
-A INPUT -p tcp --syn -m conntrack --ctstate NEW -j TCP
-A INPUT -p icmp -m conntrack --ctstate NEW -j ICMP

# Reject anything that's fallen through to this point
## Try to be protocol-specific w/ rejection message
-A INPUT -p udp -j REJECT --reject-with icmp-port-unreachable
-A INPUT -p tcp -j REJECT --reject-with tcp-reset
-A INPUT -j REJECT --reject-with icmp-proto-unreachable

# Commit the changes
COMMIT

*raw
:PREROUTING ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
COMMIT

*nat
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT

*security
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
COMMIT

*mangle
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT

sudo iptables-restore -t /etc/iptables/rules.v4
sudo nano /etc/iptables/rules.v6

*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
COMMIT

*raw
:PREROUTING DROP [0:0]
:OUTPUT DROP [0:0]
COMMIT

*nat
:PREROUTING DROP [0:0]
:INPUT DROP [0:0]
:OUTPUT DROP [0:0]
:POSTROUTING DROP [0:0]
COMMIT

*security
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
COMMIT

*mangle
:PREROUTING DROP [0:0]
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
:POSTROUTING DROP [0:0]
COMMIT

sudo ip6tables-restore -t /etc/iptables/rules.v6
sudo service netfilter-persistent reload
sudo iptables -S
sudo ip6tables -S

Lynis

Lynis to perform full system audits.

sudo apt install lynis

whowatch

To monitor active SSH connections.

sudo apt install whowatch

Remove Unused Network-Facing Services

sudo ss -atpu
sudo apt purge "package_name"

3. Web Server

Multiple configurations for regular web server needs.

1: Secure web traffic with Let's Encrypt's Certbot

2: Nginx with Server Blocks to host multiple websites

3: Apache with Virtual Host to host multiple websites

4: NodeJS and PM2 to host multiple Nuxt instances

Let's Encrypt

sudo apt install certbot

Request a certificate for Apache:

sudo certbot --apache -d domain.com -d www.domain.com

Request a certificate for Nginx:

sudo certbot --nginx -d domain.com -d www.domain.com

Certificate automated renewals:

sudo certbot renew --dry-run

Nginx

sudo apt install nginx
sudo chmod -R 755 /var/www

Nginx: New Website

Nginx folder structure.

sudo mkdir -p /var/www/your_domain/html

sudo chown -R $USER:$USER /var/www/your_domain/html
sudo chmod -R 755 /var/www/your_domain
sudo chmod -R 755 /var/www/your_domain

sample index.html

$ nano /var/www/your_domain/html/index.html

your_domain config default config file

sudo nano /etc/nginx/sites-available/your_domain

limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s;

server {
    root /var/www/website.net/html;
    index index.html index.htm index.nginx-debian.html;
    server_name website.net www.website.net;

    # Security headers
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    #add_header Referrer-Policy "no-referrer-when-downgrade" always;
    add_header Permissions-Policy "geolocation=(), microphone=(), camera=(), fullscreen=(self), payment=()";
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; font-src 'self'; form-action 'self'; frame-ancestors 'self'; upgrade-insecure-requests;" always;

    # Hide Nginx version number
    server_tokens off;

    # 404 page
    error_page 404 /404.html;

    # SSL Session Caching
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 10m;

    # OCSP Stapling
    ssl_stapling on;
    ssl_stapling_verify on;
    resolver 8.8.8.8 8.8.4.4 valid=300s;
    resolver_timeout 5s;

    # Gzip Compression
    gzip on;
    gzip_vary on;
    gzip_min_length 10240;
    gzip_proxied expired no-cache no-store private auth;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml;
    gzip_disable "MSIE [1-6]\.";

    location / {
        try_files $uri $uri/ =404;
        # Rate limiting
        limit_req zone=one burst=5;
    }

    listen [::]:443 ssl; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/website.net/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/website.net/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}

server {
    if ($host = www.website.net) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

    if ($host = website.net) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

    listen 80;
    listen [::]:80;
    server_name website.net www.website.net;
    return 404; # managed by Certbot
}

enable server block

sudo ln -s /etc/nginx/sites-available/your_domain /etc/nginx/sites-enabled/

safeguard for hash bucket memory

sudo nano /etc/nginx/nginx.conf

...
http {
    ...
    server_names_hash_bucket_size 64;
    ...
}
...

nginx verification

sudo nginx -t

sudo systemctl restart nginx

Apache

sudo apt install apache2
sudo chmod -R 755 /var/www

Enable the ssl module

sudo a2enmod ssl

Enable the proxy module

sudo a2enmod proxy

Enable the http2 module

sudo a2enmod http2

Restart Apache.

sudo systemctl restart apache2

Apache: New Website

Apache folder structure.

$ mkdir -p /var/www/domain.com/public_html/
$ touch /var/www/domain.com/public_html/index.html

Apache config for http:

$ touch /etc/apache2/sites-available/domain.com.conf

<VirtualHost *:80>
  ServerAdmin webmaster@domain.com
  ServerName domain.com
  ServerAlias www.domain.com
  DocumentRoot /var/www/domain.com/public_html/
  ErrorLog /var/www/domain.com/logs/error.log
  CustomLog /var/www/domain.com/logs/access.log combined
  Redirect permanent / https://domain.com/
</VirtualHost>

Apache config for https:

$ touch /etc/apache2/sites-available/domain.com-ssl.conf

<IfModule mod_ssl.c>
  <VirtualHost *:443>
    ServerAdmin webmaster@domain.com
    ServerName domain.com
    ServerAlias www.domain.com
    DocumentRoot /var/www/domain.com/public_html/
    ErrorLog /var/www/domain.com/logs/error.log
    CustomLog /var/www/domain.com/logs/access.log combined
    SSLCertificateFile /etc/letsencrypt/live/domain.com/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/domain.com/privkey.pem
    SSLCACertificateFile /etc/letsencrypt/live/domain.com/cert.pem
    Include /etc/letsencrypt/options-ssl-apache.conf
  </VirtualHost>
</IfModule>

Map the domain.

sudo a2ensite domain.com.conf

Restart the Apache service to register the changes.

sudo systemctl restart apache2

Node and PM2

sudo apt install nodejs
sudo apt install npm
sudo npm install pm2 -g
sudo pm2 list
sudo pm2 monit

Configuring Apache to Reserve Proxy to PM2:

<VirtualHost *:80>
  ServerAdmin webmaster@domain.com
  ServerName domain.com
  ServerAlias www.domain.com
  DocumentRoot /var/www/domain.com/public_html
  ErrorLog /var/www/domain.com/logs/error.log
  CustomLog /var/www/domain.com/logs/access.log combined

  ProxyPreserveHost On
  ProxyPass / http://localhost:3000/
  ProxyPassReverse / http://localhost:3000/

  Redirect permanent / https://domain.com/
</VirtualHost>

<IfModule mod_ssl.c>
  <VirtualHost *:443>
    ServerAdmin webmaster@domain.com
    ServerName domain.com
    ServerAlias www.domain.com
    DocumentRoot /var/www/domain.com/public_html
    ErrorLog /var/www/domain.com/logs/error.log
    CustomLog /var/www/domain.com/logs/access.log combined

    ProxyPreserveHost On
    ProxyPass / http://127.0.0.1:3000/
    ProxyPassReverse / http://127.0.0.1:3000/

    SSLCertificateFile /etc/letsencrypt/live/domain.com/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/domain.com/privkey.pem
    SSLCACertificateFile /etc/letsencrypt/live/domain.com/cert.pem
    Include /etc/letsencrypt/options-ssl-apache.conf
  </VirtualHost>
</IfModule>

4. Monitoring

Essential monitoring setup for all VPS instances.

Netdata

Real-time performance and health monitoring system. Provides immediate insight into web server performance, system resources, and potential security issues.

Install required dependencies:

sudo apt install wget curl

Install Netdata using the automatic installer

$ wget -O /tmp/netdata-kickstart.sh https://my-netdata.io/kickstart.sh
sudo sh /tmp/netdata-kickstart.sh --no-updates --stable-channel --disable-telemetry

Verify the installation

sudo systemctl status netdata

Restrict Netdata to localhost only:

sudo nano /etc/netdata/netdata.conf

[global]
    # Reduce retention to save resources (default is 3600)
    history = 1800

[web]
    # Only allow connections from localhost
    bind to = localhost
    allow connections from = localhost
    mode = static-threaded

Create a custom system configuration:

sudo nano /etc/netdata/go.d.local/web_log.conf

jobs:
  - name: nginx
    path: /var/log/nginx/access.log

  - name: apache
    path: /var/log/apache2/access.log

Create custom alerts for web hosting:

sudo nano /etc/netdata/health.d/web_alerts.conf

# High CPU Usage Alert
alarm: cpu_usage
    on: system.cpu
    lookup: average -3m unaligned of user,system,softirq,irq,guest
    units: %
    every: 1m
    warn: $this > 60
    crit: $this > 80
    info: CPU utilization exceeded threshold

# RAM Usage Alert
alarm: ram_usage
    on: system.ram
    lookup: average -1m percentage of used
    units: %
    every: 1m
    warn: $this > 70
    crit: $this > 85
    info: RAM utilization exceeded threshold

# Disk Space Alert
alarm: disk_space_usage
    on: disk.space
    lookup: average -1m percentage of used
    units: %
    every: 1m
    warn: $this > 80
    crit: $this > 90
    info: Disk space utilization exceeded threshold

# Web Server Response Time
alarm: web_response_time
    on: web_log.response_time
    lookup: average -3m
    units: ms
    every: 1m
    warn: $this > 500
    crit: $this > 1000
    info: Web server response time is too high

Restart Netdata

sudo systemctl restart netdata

Access Dashboard

From local machine:

# Create SSH tunnel to access Netdata dashboard
$ ssh -L 19999:localhost:19999 username@server_ip

# Access dashboard by opening it in the browser:
# http://localhost:19999

5. Server Maintenance

Semi-regular healthy maintenance tasks.

Lynis: System Auditing

sudo lynis show options
sudo lynis audit system

Rkhunter

sudo rkhunter -C
sudo rkhunter > ~/audits/rkhunter-audit-results.txt

chkrootkit

sudo chkrootkit > ~/audits/chkrootkit-audit-results.txt

whowatch

sudo whowatch

6. Data backup

Create backup dirs in home folder:

mkdir -p ~/backup/{sys-configs,web-configs,security,databases,custom}

Backup system configurations (these still need sudo to read):

sudo tar -czvf ~/backup/sys-configs/etc-backup.tar.gz /etc/
sudo tar -czvf ~/backup/sys-configs/ssh-config.tar.gz /etc/ssh/
sudo tar -czvf ~/backup/sys-configs/user-data.tar.gz /home/

Backup web server configurations:

sudo tar -czvf ~/backup/web-configs/nginx-sites.tar.gz /etc/nginx/sites-available/ /etc/nginx/sites-enabled/
sudo tar -czvf ~/backup/web-configs/apache-sites.tar.gz /etc/apache2/sites-available/ /etc/apache2/sites-enabled/ 2>/dev/null
sudo tar -czvf ~/backup/web-configs/www-data.tar.gz /var/www/
sudo tar -czvf ~/backup/web-configs/letsencrypt.tar.gz /etc/letsencrypt/

Backup security configurations:

sudo tar -czvf ~/backup/security/iptables-rules.tar.gz /etc/iptables/
sudo tar -czvf ~/backup/security/fail2ban.tar.gz /etc/fail2ban/
sudo tar -czvf ~/backup/security/crowdsec.tar.gz /etc/crowdsec/ 2>/dev/null

Backup node and pm2:

if command -v pm2 &> /dev/null; then
pm2 save
tar -czvf ~/backup/custom/pm2-config.tar.gz ~/.pm2/ 2>/dev/null
fi

Create a list of installed packages

dpkg --get-selections > ~/backup/sys-configs/installed-packages.txt

Create a snapshot of current system state

sudo apt install -y debsums
sudo debsums -s -c > ~/backup/sys-configs/modified-config-files.txt 2>&1

Create snapshot of file permissions in /etc

sudo find /etc -type f -exec stat -c "%a %n" {} \; > ~/backup/sys-configs/etc-permissions.txt

Fix ownership of all backup files

sudo chown -R $(whoami):$(whoami) ~/master-backup

Encrypt all backups

cd ~
tar -czvf vps-backup.tar.gz backup/
gpg --symmetric --cipher-algo AES256 vps-backup.tar.gz

rsync the encrypted backups from VPS to local machine:

rsync -ahvz username@vps-ip:~/vps-backup.tar.gz ~/local-backups/

Extract and decrypt backups on local machine:

gpg -d /path/to/local/encrypted_backups/vps-backup-home.tar.gz.gpg | tar xzvf -

7. Upgrade Process (Debian 12 Bookworm)

Preliminary Steps:

# current system full update
sudo apt update
sudo apt upgrade
sudo apt full-upgrade

# remove unnecessary packages
sudo apt --purge autoremove

# check if any packages are on hold
apt-mark showhold

Update Sources List:

# backup sources list
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bullseye.bak

# create new sources list for Bookworm
sudo nano /etc/apt/sources.list

/etc/apt/sources.list:

deb http://deb.debian.org/debian bookworm main contrib non-free-firmware non-free
# deb-src http://deb.debian.org/debian bookworm main contrib non-free-firmware non-free

deb http://security.debian.org/debian-security bookworm-security main contrib non-free-firmware non-free
# deb-src http://security.debian.org/debian-security bookworm-security main contrib non-free-firmware non-free

deb http://deb.debian.org/debian bookworm-updates main contrib non-free-firmware non-free
# deb-src http://deb.debian.org/debian bookworm-updates main contrib non-free-firmware non-free

# FastTrack repository (requires separate installation in Bookworm)
# Will be configured after upgrade

Perform the upgrade:

# update package index with new sources
sudo apt update

# upgrade minimal essential packages
sudo apt upgrade --without-new-pkgs

# execute full dist-upgrade
sudo apt full-upgrade

# clean-up obsolete packages
sudo apt --purge autoremove

# re-install fasttrack for Bookworm (setup is different in Bookworm)
sudo apt install fasttrack-archive-keyring
sudo sh -c 'cat > /etc/apt/sources.list.d/fasttrack.list << EOF
deb https://fasttrack.debian.net/debian-fasttrack/ bookworm-fasttrack main contrib non-free
# deb-src https://fasttrack.debian.net/debian-fasttrack/ bookworm-fasttrack main contrib non-free
EOF'

# last update
sudo apt update

Post-Upgrade Tasks:

# check for held or broken packages
sudo apt-mark showhold
sudo dpkg --audit
sudo apt --fix-broken install

# restart system to use the new kernel
sudo shutdown -r now

# post-reboot: verify version
lsb_release -a
uname -a

# re-install/re-config critical security components
sudo apt reinstall fail2ban
sudo systemctl restart fail2ban
sudo systemctl status fail2ban

# re-configure Crowdsec
if systemctl is-active --quiet crowdsec; then
    sudo apt reinstall crowdsec crowdsec-nginx-bouncer
    sudo systemctl restart crowdsec
    sudo systemctl status crowdsec
fi

# verify firewall rules are intact
sudo iptables -L
sudo service netfilter-persistent reload

# update and verify web server configs
if systemctl is-active --quiet nginx; then
    sudo nginx -t
    sudo systemctl restart nginx
fi

if systemctl is-active --quiet apache2; then
    sudo apache2ctl configtest
    sudo systemctl restart apache2
fi

# check for any overwritten modified files
sudo debsums -s -c

Post-upgrade Security Verification:

# run security audit with Lynis
sudo lynis audit system

# comprehensive security checks
sudo fail2ban-client status
sudo systemctl status crowdsec
sudo netstat -tulpn | grep "LISTEN"
sudo lynis audit system
sudo rkhunter --check
sudo chkrootkit

# update SSL security settings for web servers
# Verify TLS 1.3 is enabled and older protocols disabled
sudo nano /etc/letsencrypt/options-ssl-nginx.conf

8. Bootstraps

A bunch of opinionated and hardened files for multiple software configs:

Name		Name	Last commit message	Last commit date
Latest commit History 15 Commits
apache2		apache2
fail2ban		fail2ban
gnupg		gnupg
iptables		iptables
nginx		nginx
postfix		postfix
sshd		sshd
README.md		README.md

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debian-seed

1. Basic server configuration

System update && upgrade

Hostname change

Update /etc/hosts

Timezone setup

New user

Sudo

Fish

Reboot

2. Hardening

SSH hardening and daemon configuration

Fail2ban

Crowdsec

Installation

Integration with fail2ban

Firewall

Lynis

whowatch

Remove Unused Network-Facing Services

3. Web Server

Let's Encrypt

Nginx

Nginx: New Website

Apache

Apache: New Website

Node and PM2

4. Monitoring

Netdata

Access Dashboard

5. Server Maintenance

Lynis: System Auditing

Rkhunter

chkrootkit

whowatch

6. Data backup

7. Upgrade Process (Debian 12 Bookworm)

8. Bootstraps

apache2

fail2ban

fish

iptables

gnupg

nginx

postfix

sshd

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