Tutorial Lengkap Membuat SMTP Relay Server dengan Mailcow + Docker

# Add Docker's official GPG key:
sudo apt-get update
sudo apt-get install ca-certificates curl
sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc

# Add the repository to Apt sources:
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
  $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update

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

cd /opt
git clone https://github.com/mailcow/mailcow-dockerized
cd mailcow-dockerized
./generate_config.sh

docker compose pull
docker compose up -d

sudo mkdir -p data/conf/postfix
sudo bash -c 'cat > data/conf/postfix/extra.cf <<EOF
default_process_limit = 200
smtp_destination_concurrency_limit = 50
smtp_destination_rate_delay = 0s
EOF'
docker compose restart postfix-mailcow

sudo mkdir -p data/conf/rspamd/local.d
sudo bash -c 'cat > data/conf/rspamd/local.d/ratelimit.conf <<EOF
rates {
  per_user = {
    key = "user.lower";
    bucket = [
      { burst = 1000; rate = "600 / 1min"; }
    ];
    message = "Guard: minute rate limit exceeded for this user";
  }
  per_ip = {
    key = "ip";
    bucket = [
      { burst = 600; rate = "400 / 1min"; }
    ];
    message = "Guard: minute rate limit exceeded for this IP";
  }
}
EOF'

sudo bash -c 'cat > data/conf/rspamd/scores.d/ratelimit.conf <<EOF
symbols = {
  RATELIMITED = { weight = 0.0; description = "Minute guard telemetry only"; };
}
EOF'

docker compose exec rspamd-mailcow rspamadm configtest
docker compose restart rspamd-mailcow

sudo mkdir -p data/conf/rspamd/maps.d
sudo touch data/conf/rspamd/maps.d/whitelist.map
sudo bash -c 'cat > data/conf/rspamd/local.d/multimap.conf <<EOF
MAILCOW_WHITE {
  type = "from";
  filter = "email:addr";
  map = "$LOCAL_CONFDIR/maps.d/whitelist.map";
  description = "Global whitelist (UI)";
  group = "policies";
  action = "accept";
}
EOF'
docker compose exec rspamd-mailcow rspamadm configtest
docker compose restart rspamd-mailcow

swaks --server smtp.example.com --auth LOGIN --au me@example.com --ap 'PASSWORD' --to target@gmail.com --from me@example.com

docker compose logs -f postfix-mailcow
docker compose logs -f rspamd-mailcow | grep RATELIMIT