Forward Email Self-Hosting Installation Guide for Debian

This guide provides step-by-step instructions for installing Forward Email's self-hosted solution on Debian systems. This guide is specifically tailored for Debian 11 (Bullseye) and Debian 12 (Bookworm).

Before beginning the installation, ensure you have:

  • Debian Server: Version 11 (Bullseye) or 12 (Bookworm)
  • Root Access: You must be able to run commands as root (sudo access)
  • Domain Name: A domain that you control with DNS management access
  • Clean Server: Recommended to use a fresh Debian installation
  • Internet Connection: Required for downloading packages and Docker images

  • RAM: Minimum 2GB (4GB recommended for production)
  • Storage: Minimum 20GB available space (50GB+ recommended for production)
  • CPU: 1 vCPU minimum (2+ vCPUs recommended for production)
  • Network: Public IP address with the following ports accessible:
    • 22 (SSH)
    • 25 (SMTP)
    • 80 (HTTP)
    • 443 (HTTPS)
    • 465 (SMTPS)
    • 993 (IMAPS)
    • 995 (POP3S)

Step 1: Initial System Setup

First, ensure your system is up to date and switch to root user:

# Update system packages
sudo apt update && sudo apt upgrade -y

Switch to root user (required for the installation)


sudo su -

Step 2: Configure DNS Resolvers

Configure your system to use Cloudflare's DNS servers for reliable certificate generation:

# Stop and disable systemd-resolved if running
if systemctl is-active --quiet systemd-resolved; then
    rm /etc/resolv.conf
    systemctl stop systemd-resolved
    systemctl disable systemd-resolved
    systemctl mask systemd-resolved
fi

Configure Cloudflare DNS resolvers


tee /etc/resolv.conf > /dev/null <<EOF
nameserver 1.1.1.1
nameserver 2606:4700:4700::1111
nameserver 1.0.0.1
nameserver 2606:4700:4700::1001
nameserver 8.8.8.8
nameserver 2001:4860:4860::8888
nameserver 8.8.4.4
nameserver 2001:4860:4860::8844
EOF

Step 3: Install System Dependencies

Install the required packages for Forward Email on Debian:

# Update package list
apt-get update -y

Install basic dependencies (Debian-specific package list)


apt-get install -y 

ca-certificates 

curl 

gnupg 

git 

openssl 

lsb-release 

apt-transport-https 

software-properties-common

Step 4: Install and Configure Snapd

Debian doesn't include snapd by default, so we need to install and configure it:

# Install snapd
apt-get install -y snapd

Enable and start snapd service


systemctl enable snapd
systemctl start snapd


Create symlink for snap to work properly


ln -sf /var/lib/snapd/snap /snap


Wait for snapd to be ready


sleep 10


Verify snapd is working


snap version

Step 5: Install Snap Packages

Install AWS CLI and Certbot via snap:

# Install AWS CLI
snap install aws-cli --classic

Install Certbot and DNS plugin


snap install certbot --classic
snap set certbot trust-plugin-with-root=ok
snap install certbot-dns-cloudflare


Verify installations


aws --version
certbot --version

Step 6: Install Docker

Install Docker CE and Docker Compose on Debian:

# Add Docker's official GPG key (Debian-specific)
install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/debian/gpg | tee /etc/apt/keyrings/docker.asc
chmod a+r /etc/apt/keyrings/docker.asc

Add Docker repository (Debian-specific)


echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/debian $(lsb_release -cs) stable" | tee /etc/apt/sources.list.d/docker.list


Update package index and install Docker


apt-get update -y
apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin


Install standalone docker-compose as fallback (if plugin doesn't work)


if ! command -v docker-compose &> /dev/null; then
apt-get install -y docker-compose
fi


Verify Docker installation


docker --version
docker compose version || docker-compose --version

Step 7: Configure Docker Service

Ensure Docker starts automatically and is running:

# Enable and start Docker service
systemctl unmask docker
systemctl enable docker
systemctl start docker

Verify Docker is running


docker info

If Docker fails to start, try starting it manually:

# Alternative startup method if systemctl fails
nohup dockerd >/dev/null 2>/dev/null &
sleep 5
docker info

Step 8: Install and Configure UFW Firewall

Debian minimal installations may not include UFW, so install it first:

# Install UFW if not present
if ! command -v ufw &> /dev/null; then
    apt-get update -y
    apt-get install -y ufw
fi

Set default policies


ufw default deny incoming
ufw default allow outgoing


Allow SSH (important - don't lock yourself out!)


ufw allow 22/tcp


Allow email-related ports


ufw allow 25/tcp    # SMTP
ufw allow 80/tcp    # HTTP (for Let's Encrypt)
ufw allow 443/tcp   # HTTPS
ufw allow 465/tcp   # SMTPS
ufw allow 993/tcp   # IMAPS
ufw allow 995/tcp   # POP3S
ufw allow 2993/tcp  # IMAP (alternative port)
ufw allow 2995/tcp  # POP3 (alternative port)
ufw allow 3456/tcp  # Custom service port
ufw allow 4000/tcp  # Custom service port
ufw allow 5000/tcp  # Custom service port


Allow local database connections


ufw allow from 127.0.0.1 to any port 27017  # MongoDB
ufw allow from 127.0.0.1 to any port 6379   # Redis


Enable firewall


echo "y" | ufw enable


Check firewall status


ufw status numbered

Step 9: Clone Forward Email Repository

Download the Forward Email source code:

# Set up variables
REPO_FOLDER_NAME="forwardemail.net"
REPO_URL="https://github.com/forwardemail/forwardemail.net.git"
ROOT_DIR="/root/$REPO_FOLDER_NAME"

Clone the repository


git clone "$REPO_URL" "$ROOT_DIR"
cd "$ROOT_DIR"


Verify the clone was successful


ls -la

Step 10: Set Up Environment Configuration

Prepare the environment configuration:

# Set up directory variables
SELF_HOST_DIR="$ROOT_DIR/self-hosting"
ENV_FILE_DEFAULTS=".env.defaults"
ENV_FILE=".env"

Copy default environment file


cp "$ROOT_DIR/$ENV_FILE_DEFAULTS" "$SELF_HOST_DIR/$ENV_FILE"


Create SSL directory


mkdir -p "$SELF_HOST_DIR/ssl"


Create database directories


mkdir -p "$SELF_HOST_DIR/sqlite-data"
mkdir -p "$SELF_HOST_DIR/mongo-backups"
mkdir -p "$SELF_HOST_DIR/redis-backups"

Step 11: Configure Your Domain

Set your domain name and update environment variables:

# Replace 'yourdomain.com' with your actual domain
DOMAIN="yourdomain.com"

Function to update environment file


update_env_file() {
local key="$1"
local value="$2"


if grep -qE "^${key}=" "$SELF_HOST_DIR/$ENV_FILE"; then
sed -i -E "s|^${key}=.*|${key}=${value}|" "$SELF_HOST_DIR/$ENV_FILE"
else
echo "${key}=${value}" >> "$SELF_HOST_DIR/$ENV_FILE"
fi
}


Update domain-related environment variables


update_env_file "DOMAIN" "$DOMAIN"
update_env_file "NODE_ENV" "production"
update_env_file "HTTP_PROTOCOL" "https"
update_env_file "WEB_HOST" "$DOMAIN"
update_env_file "WEB_PORT" "443"
update_env_file "CALDAV_HOST" "caldav.$DOMAIN"
update_env_file "CARDDAV_HOST" "carddav.$DOMAIN"
update_env_file "API_HOST" "api.$DOMAIN"
update_env_file "APP_NAME" "$DOMAIN"
update_env_file "SMTP_HOST" "smtp.$DOMAIN"
update_env_file "SMTP_PORT" "465"
update_env_file "IMAP_HOST" "imap.$DOMAIN"
update_env_file "IMAP_PORT" "993"
update_env_file "POP3_HOST" "pop3.$DOMAIN"
update_env_file "POP3_PORT" "995"
update_env_file "MX_HOST" "mx.$DOMAIN"
update_env_file "SMTP_EXCHANGE_DOMAINS" "mx.$DOMAIN"
update_env_file "SELF_HOSTED" "true"
update_env_file "WEBSITE_URL" "$DOMAIN"
update_env_file "AUTH_BASIC_ENABLED" "true"

Step 12: Generate SSL Certificates

# Generate certificates using manual DNS challenge
certbot certonly \
  --manual \
  --agree-tos \
  --preferred-challenges dns \
  -d "*.$DOMAIN" \
  -d "$DOMAIN"

Important: When prompted, you'll need to create TXT records in your DNS. You may see multiple challenges for the same domain - create ALL of them. Do not remove the first TXT record when adding the second one.

Option B: Cloudflare DNS (If you use Cloudflare)

If your domain uses Cloudflare for DNS, you can automate certificate generation:

# Create Cloudflare credentials file
cat > /root/.cloudflare.ini <<EOF
dns_cloudflare_email = "your-email@example.com"
dns_cloudflare_api_key = "your-cloudflare-global-api-key"
EOF

Set proper permissions


chmod 600 /root/.cloudflare.ini


Generate certificates automatically


certbot certonly 

--dns-cloudflare 

--dns-cloudflare-credentials /root/.cloudflare.ini 

-d "$DOMAIN" 

-d "*.$DOMAIN" 

--non-interactive 

--agree-tos 

--email "your-email@example.com"

Copy Certificates

After certificate generation, copy them to the application directory:

# Copy certificates to application SSL directory
cp /etc/letsencrypt/live/$DOMAIN*/* "$SELF_HOST_DIR/ssl/"

Verify certificates were copied


ls -la "$SELF_HOST_DIR/ssl/"

Step 13: Generate Encryption Keys

Create the various encryption keys required for secure operation:

# Generate helper encryption key
helper_encryption_key=$(openssl rand -base64 32 | tr -d /=+ | cut -c -32)
update_env_file "HELPER_ENCRYPTION_KEY" "$helper_encryption_key"

Generate SRS secret for email forwarding


srs_secret=$(openssl rand -base64 32 | tr -d /=+ | cut -c -32)
update_env_file "SRS_SECRET" "$srs_secret"


Generate TXT encryption key


txt_encryption_key=$(openssl rand -hex 16)
update_env_file "TXT_ENCRYPTION_KEY" "$txt_encryption_key"


Generate DKIM private key for email signing


openssl genrsa -f4 -out "$SELF_HOST_DIR/ssl/dkim.key" 2048
update_env_file "DKIM_PRIVATE_KEY_PATH" "/app/ssl/dkim.key"


Generate webhook signature key


webhook_signature_key=$(openssl rand -hex 16)
update_env_file "WEBHOOK_SIGNATURE_KEY" "$webhook_signature_key"


Set SMTP transport password


update_env_file "SMTP_TRANSPORT_PASS" "$(openssl rand -base64 32)"


echo "✅ All encryption keys generated successfully"

Step 14: Update SSL Paths in Configuration

Configure the SSL certificate paths in the environment file:

# Update SSL paths to point to the correct certificate files
sed -i -E \
  -e 's|^(.*_)?SSL_KEY_PATH=.*|\1SSL_KEY_PATH=/app/ssl/privkey.pem|' \
  -e 's|^(.*_)?SSL_CERT_PATH=.*|\1SSL_CERT_PATH=/app/ssl/fullchain.pem|' \
  -e 's|^(.*_)?SSL_CA_PATH=.*|\1SSL_CA_PATH=/app/ssl/chain.pem|' \
  "$SELF_HOST_DIR/$ENV_FILE"

Step 15: Set Up Basic Authentication

Create temporary basic authentication credentials:

# Generate a secure random password
PASSWORD=$(openssl rand -base64 16)

Update environment file with basic auth credentials


update_env_file "AUTH_BASIC_USERNAME" "admin"
update_env_file "AUTH_BASIC_PASSWORD" "$PASSWORD"


Display credentials (save these!)


echo ""
echo "🔐 IMPORTANT: Save these login credentials!"
echo "=================================="
echo "Username: admin"
echo "Password: $PASSWORD"
echo "=================================="
echo ""
echo "You'll need these to access the web interface after installation."
echo ""

Step 16: Deploy with Docker Compose

Start all the Forward Email services:

# Set Docker Compose file path
DOCKER_COMPOSE_FILE="$SELF_HOST_DIR/docker-compose-self-hosted.yml"

Stop any existing containers


if command -v docker-compose &> /dev/null; then
docker-compose -f "$DOCKER_COMPOSE_FILE" down
else
docker compose -f "$DOCKER_COMPOSE_FILE" down
fi


Pull the latest images


if command -v docker-compose &> /dev/null; then
docker-compose -f "$DOCKER_COMPOSE_FILE" pull
else
docker compose -f "$DOCKER_COMPOSE_FILE" pull
fi


Start all services in detached mode


if command -v docker-compose &> /dev/null; then
docker-compose -f "$DOCKER_COMPOSE_FILE" up -d
else
docker compose -f "$DOCKER_COMPOSE_FILE" up -d
fi


Wait a moment for services to start


sleep 10


Check service status


if command -v docker-compose &> /dev/null; then
docker-compose -f "$DOCKER_COMPOSE_FILE" ps
else
docker compose -f "$DOCKER_COMPOSE_FILE" ps
fi

Step 17: Verify Installation

Check that all services are running correctly:

# Check Docker containers
docker ps

Check service logs for any errors


if command -v docker-compose &> /dev/null; then
docker-compose -f "$DOCKER_COMPOSE_FILE" logs --tail=50
else
docker compose -f "$DOCKER_COMPOSE_FILE" logs --tail=50
fi


Test web interface connectivity


curl -I https://$DOMAIN


Check if ports are listening


ss -tlnp | grep -E ':(25|80|443|465|587|993|995)'

DNS Records Setup

You need to configure the following DNS records for your domain:

MX Record

@ MX 10 mx.yourdomain.com

A Records

@ A YOUR_SERVER_IP
mx A YOUR_SERVER_IP
smtp A YOUR_SERVER_IP
imap A YOUR_SERVER_IP
pop3 A YOUR_SERVER_IP
api A YOUR_SERVER_IP
caldav A YOUR_SERVER_IP
carddav A YOUR_SERVER_IP

SPF Record

@ TXT "v=spf1 mx ~all"

DKIM Record

Get your DKIM public key:

# Extract DKIM public key
openssl rsa -in "$SELF_HOST_DIR/ssl/dkim.key" -pubout -outform DER | openssl base64 -A

Create DKIM DNS record:

default._domainkey TXT "v=DKIM1; k=rsa; p=YOUR_DKIM_PUBLIC_KEY"

DMARC Record

_dmarc TXT "v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com"

First Login

  1. Open your web browser and navigate to https://yourdomain.com
  2. Enter the basic authentication credentials you saved earlier
  3. Complete the initial setup wizard
  4. Create your first email account

Set Up S3-Compatible Backup

Configure automated backups to S3-compatible storage:

# Create AWS credentials directory
mkdir -p ~/.aws

Configure AWS credentials


cat > ~/.aws/credentials <<EOF
[default]
aws_access_key_id = YOUR_ACCESS_KEY_ID
aws_secret_access_key = YOUR_SECRET_ACCESS_KEY
EOF


Configure AWS settings


cat > ~/.aws/config <<EOF
[default]
region = auto
output = json
EOF


For non-AWS S3 (like Cloudflare R2), add endpoint URL


echo "endpoint_url = YOUR_S3_ENDPOINT_URL" >> ~/.aws/config

Set Up Backup Cron Jobs

# Make backup scripts executable
chmod +x "$ROOT_DIR/self-hosting/scripts/backup-mongo.sh"
chmod +x "$ROOT_DIR/self-hosting/scripts/backup-redis.sh"

Add MongoDB backup cron job (runs daily at midnight)


(crontab -l 2>/dev/null; echo "0 0 * * * $ROOT_DIR/self-hosting/scripts/backup-mongo.sh >> /var/log/mongo-backup.log 2>&1") | crontab -


Add Redis backup cron job (runs daily at midnight)


(crontab -l 2>/dev/null; echo "0 0 * * * $ROOT_DIR/self-hosting/scripts/backup-redis.sh >> /var/log/redis-backup.log 2>&1") | crontab -


Verify cron jobs were added


crontab -l

Set up automatic updates for your Forward Email installation:

# Create auto-update command (use appropriate docker compose command)
if command -v docker-compose &> /dev/null; then
    DOCKER_UPDATE_CMD="docker-compose -f $DOCKER_COMPOSE_FILE pull && docker-compose -f $DOCKER_COMPOSE_FILE up -d"
else
    DOCKER_UPDATE_CMD="docker compose -f $DOCKER_COMPOSE_FILE pull && docker compose -f $DOCKER_COMPOSE_FILE up -d"
fi

Add auto-update cron job (runs daily at 1 AM)


(crontab -l 2>/dev/null; echo "0 1 * * * $DOCKER_UPDATE_CMD >> /var/log/autoupdate.log 2>&1") | crontab -


Verify the cron job was added


crontab -l

Package Management Differences

  • Snapd: Not installed by default on Debian, requires manual installation
  • Docker: Uses Debian-specific repositories and GPG keys
  • UFW: May not be included in minimal Debian installations
  • systemd: Behavior may differ slightly from Ubuntu

Service Management

# Check service status (Debian-specific commands)
systemctl status snapd
systemctl status docker
systemctl status ufw

Restart services if needed


systemctl restart snapd
systemctl restart docker

Network Configuration

Debian may have different network interface names or configurations:

# Check network interfaces
ip addr show

Check routing


ip route show


Check DNS resolution


nslookup google.com

Log Locations

  • Docker Compose logs: Use appropriate docker compose command based on installation
  • System logs: /var/log/syslog
  • Backup logs: /var/log/mongo-backup.log, /var/log/redis-backup.log
  • Auto-update logs: /var/log/autoupdate.log
  • Snapd logs: journalctl -u snapd

Regular Maintenance Tasks

  1. Monitor disk space: df -h
  2. Check service status: Use appropriate docker compose command
  3. Review logs: Check both application and system logs
  4. Update system packages: apt update && apt upgrade
  5. Monitor snapd: snap list a snap refresh

Certificate Renewal

Certificates should auto-renew, but you can manually renew if needed:

# Manual certificate renewal
certbot renew

Copy renewed certificates


cp /etc/letsencrypt/live/$DOMAIN*/* "$SELF_HOST_DIR/ssl/"


Restart services to use new certificates


if command -v docker-compose &> /dev/null; then
docker-compose -f "$DOCKER_COMPOSE_FILE" restart
else
docker compose -f "$DOCKER_COMPOSE_FILE" restart
fi

Debian-Specific Issues

1. Snapd Not Working

# Check snapd status
systemctl status snapd

Restart snapd


systemctl restart snapd


Check snap path


echo $PATH | grep snap


Add snap to PATH if missing


echo 'export PATH=$PATH:/snap/bin' >> ~/.bashrc
source ~/.bashrc

2. Docker Compose Command Not Found

# Check which docker compose command is available
command -v docker-compose
command -v docker

Use the appropriate command in scripts


if command -v docker-compose &> /dev/null; then
echo "Using docker-compose"
else
echo "Using docker compose"
fi

3. Package Installation Issues

# Update package cache
apt update

Fix broken packages


apt --fix-broken install


Check for held packages


apt-mark showhold

Common Issues

1. Docker Service Won't Start

# Check Docker status
systemctl status docker

Check Docker logs


journalctl -u docker


Try alternative startup


nohup dockerd >/dev/null 2>/dev/null &

2. Certificate Generation Fails

  • Ensure ports 80 and 443 are accessible
  • Verify DNS records point to your server
  • Check firewall settings with ufw status

3. Email Delivery Issues

  • Verify MX records are correct
  • Check SPF, DKIM, and DMARC records
  • Ensure port 25 isn't blocked by your hosting provider

Getting Help

  1. Keep System Updated: Regularly update Debian and packages
  2. Monitor Logs: Set up log monitoring and alerting
  3. Backup Regularly: Test backup and restore procedures
  4. Use Strong Passwords: Generate strong passwords for all accounts
  5. Enable Fail2Ban: Consider installing fail2ban for additional security
  6. Regular Security Audits: Periodically review your configuration
  7. Monitor Snapd: Keep snap packages updated with snap refresh

Your Forward Email self-hosted installation should now be complete and running on Debian. Remember to:

  1. Configure your DNS records properly
  2. Test email sending and receiving
  3. Set up regular backups
  4. Monitor your system regularly
  5. Keep your installation updated
  6. Monitor snapd and snap packages

The main differences from Ubuntu are the snapd installation and Docker repository configuration. Once these are properly set up, the Forward Email application behaves identically on both systems.

For additional configuration options and advanced features, refer to the official Forward Email documentation at https://forwardemail.net/self-hosted#configuration.