diff --git a/Dockerfile b/Dockerfile
index d3287a0424a6514c89eba4b880557c519f77d614..97b69907a0387aeb73f013cef1f110026aa79b1a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,19 +1,11 @@
-# Stage 1: build the tiny smtp server
-FROM golang:1.16 AS build
-WORKDIR /go/src
-COPY go.mod .
-COPY go.sum .
-COPY smtpd.go .
-RUN go build -o smtpd smtpd.go
+# Stage 1: import the smtpd-pipe server
+FROM registry.git.autistici.org/ai3/tools/smtpd-pipe:master AS smtpd
 
 # Stage 2: build the final container
-FROM registry.git.autistici.org/ai3/docker/apache2-base:master
-COPY start.sh /start.sh
+FROM registry.git.autistici.org/ai3/docker/apache2-base:s6
 COPY build.sh /tmp/build.sh
 COPY ai-lurker-ui.patch /tmp/ai-lurker-ui.patch
 COPY conf/ /etc/
-COPY --from=build /go/src/smtpd /usr/bin/smtpd
+COPY --from=smtpd /smtpd /usr/bin/smtpd
 RUN /tmp/build.sh && rm /tmp/build.sh /tmp/ai-lurker-ui.patch
 COPY logo.png /var/lib/lurker-www-orig/logo.png
-ENTRYPOINT ["/usr/local/bin/chaperone"]
-
diff --git a/build.sh b/build.sh
index 7269705581611d3941910ad68cbd68360b1b87d4..126ba742a3de180d58f9efd1b295ab6dee76c84c 100755
--- a/build.sh
+++ b/build.sh
@@ -22,7 +22,7 @@ die() {
 
 set -x
 
-# Install packages (aiosmtpd comes from backports in stretch).
+# Install packages.
 apt-get -q update
 install_packages ${BUILD_PACKAGES} ${PACKAGES} \
     || die "could not install packages"
diff --git a/conf/chaperone.d/prune.conf b/conf/chaperone.d/prune.conf
deleted file mode 100644
index e50cd00b241b5b4b861311ce71156ae1447d4935..0000000000000000000000000000000000000000
--- a/conf/chaperone.d/prune.conf
+++ /dev/null
@@ -1,5 +0,0 @@
-lurker-prune.service: {
-    type: cron,
-    interval: "*/15 * * * *",
-    command: "/usr/bin/lurker-prune",
-}
diff --git a/conf/chaperone.d/smtpd.conf b/conf/chaperone.d/smtpd.conf
deleted file mode 100644
index 9943f2d23c966134b29617525f1488ca072bb3a0..0000000000000000000000000000000000000000
--- a/conf/chaperone.d/smtpd.conf
+++ /dev/null
@@ -1,5 +0,0 @@
-smtpd.service: {
-  command: "/usr/bin/smtpd",
-  exit_kills: true,
-}
-
diff --git a/conf/chaperone.d/start.conf b/conf/chaperone.d/start.conf
deleted file mode 100644
index 22550abae56b25aa95f7d2a675a87769ad359cc9..0000000000000000000000000000000000000000
--- a/conf/chaperone.d/start.conf
+++ /dev/null
@@ -1,7 +0,0 @@
-lurker_setup.service: {
-    type: oneshot,
-    stdout: inherit,
-    service_groups: INIT,
-    process_timeout: 60,
-    command: "/start.sh",
-}
diff --git a/start.sh b/conf/cont-init.d/90lurker-setup
similarity index 100%
rename from start.sh
rename to conf/cont-init.d/90lurker-setup
diff --git a/conf/services.d/prune/run b/conf/services.d/prune/run
new file mode 100755
index 0000000000000000000000000000000000000000..c3490ec7e25c3a6e68ffe8712ea7b81a767e5ae1
--- /dev/null
+++ b/conf/services.d/prune/run
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+period=900
+
+while true; do
+  sleep $period
+  /usr/bin/lurker-prune
+done
diff --git a/conf/services.d/smtpd/finish b/conf/services.d/smtpd/finish
new file mode 100755
index 0000000000000000000000000000000000000000..b6531b3ca574205c9e78650dbd7c38718683e57c
--- /dev/null
+++ b/conf/services.d/smtpd/finish
@@ -0,0 +1,3 @@
+#!/usr/bin/execlineb -S0
+
+s6-svscanctl -t /var/run/s6/services
diff --git a/conf/services.d/smtpd/run b/conf/services.d/smtpd/run
new file mode 100755
index 0000000000000000000000000000000000000000..2934c3bb2a8cd5eb92d627831c3fa6a296ccd255
--- /dev/null
+++ b/conf/services.d/smtpd/run
@@ -0,0 +1,12 @@
+#!/bin/sh
+
+# Build the SMTP_RULES env var based on the LURKER_ADDR_RX regexp.
+export SMTP_RULES="${LURKER_ADDR_RX}:/usr/bin/lurker-index -m -l \\1"
+
+# Temporarily suspend incoming email when lurker is rebuilding its index.
+export SMTP_GUARD_FILE="${LURKER_DATA_DIR:-/var/lib/lurker/data}/.tmp"
+
+# Allow large messages (50MB).
+export SMTP_MAX_MESSAGE_SIZE=52428800
+
+exec /usr/bin/smtpd
diff --git a/go.mod b/go.mod
deleted file mode 100644
index dcd5b8502bac1a64da4483e902a5e9ebfa78c2cf..0000000000000000000000000000000000000000
--- a/go.mod
+++ /dev/null
@@ -1,5 +0,0 @@
-module git.autistici.org/ai3/docker/lurker
-
-go 1.14
-
-require github.com/chrj/smtpd v0.3.0
diff --git a/go.sum b/go.sum
deleted file mode 100644
index a6779b97bdb3585dc6fd9f5779e0c5c23ac1ce3f..0000000000000000000000000000000000000000
--- a/go.sum
+++ /dev/null
@@ -1,3 +0,0 @@
-github.com/chrj/smtpd v0.3.0 h1:cw1LSHDOz7N3XbkcZSF/bue9dh7ATKk5ZksfBztV6b0=
-github.com/chrj/smtpd v0.3.0/go.mod h1:1hmG9KbrE10JG1SmvG79Krh4F6713oUrw2+gRp1oSYk=
-github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb/go.mod h1:FSCIHbrqk7D01Mj8y/jW+NS1uoCerr+ad+IckTHTFf4=
diff --git a/smtpd.go b/smtpd.go
deleted file mode 100644
index 51709f258eec98517a2064cb9c047a80e682e7ed..0000000000000000000000000000000000000000
--- a/smtpd.go
+++ /dev/null
@@ -1,118 +0,0 @@
-// Simple SMTP server that runs lurker-index.
-//
-// Use the --addr-rx command-line option to extract the list name from
-// the recipient address. The same regexp defines valid recipient
-// addresses (messages whose recipient do not match are rejected).
-//
-package main
-
-import (
-	"bytes"
-	"flag"
-	"fmt"
-	"log"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"regexp"
-	"strconv"
-	"strings"
-
-	"github.com/chrj/smtpd"
-)
-
-var (
-	port          = flag.Int("port", getenvInt("SMTP_PORT"), "smtp port")
-	hostname      = flag.String("ehlo-hostname", os.Getenv("SMTP_EHLO_HOSTNAME"), "EHLO hostname")
-	lurkerDataDir = flag.String("lurker-data-dir", getenvDefault("LURKER_DATA_DIR", "/var/lib/lurker/data"), "lurker data dir")
-	addrPattern   = flag.String("addr-rx", getenvDefault("LURKER_ADDR_RX", `lurker\+([^@]+)@.*`), "recipient address regular expression")
-)
-
-var addrRx *regexp.Regexp
-
-func getenvInt(key string) int {
-	n, _ := strconv.Atoi(os.Getenv(key))
-	return n
-}
-
-func getenvDefault(key, dflt string) string {
-	if s := os.Getenv(key); s != "" {
-		return s
-	}
-	return dflt
-}
-
-func isMaintenanceModeOn() bool {
-	_, err := os.Stat(filepath.Join(*lurkerDataDir, ".tmp"))
-	return !os.IsNotExist(err)
-}
-
-func lurkerIndexMsg(listName string, data []byte) error {
-	cmd := exec.Command("lurker-index", "-m", "-l", listName)
-	cmd.Stdin = bytes.NewReader(data)
-	out, err := cmd.CombinedOutput()
-	if err != nil {
-		outStr := strings.Replace(strings.TrimSpace(string(out)), "\n", "; ", -1)
-		log.Printf("lurker-index error: %v, %s", err, outStr)
-		return smtpd.Error{550, outStr}
-	}
-	return nil
-}
-
-func parseRecipientAddr(addr string) (string, error) {
-	m := addrRx.FindStringSubmatch(addr)
-	if len(m) == 0 {
-		return "", smtpd.Error{550, "Unknown recipient"}
-	}
-	listName := m[1]
-	if listName == "" {
-		return "", smtpd.Error{550, "No list name found"}
-	}
-	return listName, nil
-}
-
-func checkRecipient(peer smtpd.Peer, addr string) error {
-	_, err := parseRecipientAddr(addr)
-	return err
-}
-
-func handleMessage(peer smtpd.Peer, env smtpd.Envelope) error {
-	if isMaintenanceModeOn() {
-		return smtpd.Error{421, "Maintenance mode, retry later"}
-	}
-
-	log.Printf("received msg: %s -> %s", env.Sender, strings.Join(env.Recipients, ","))
-	for _, rcpt := range env.Recipients {
-		listName, err := parseRecipientAddr(rcpt)
-		if err != nil {
-			return err
-		}
-		if err := lurkerIndexMsg(listName, env.Data); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func main() {
-	log.SetFlags(0)
-	flag.Parse()
-
-	// Auto-anchor the addr regexp.
-	var err error
-	addrRx, err = regexp.Compile(fmt.Sprintf("^%s$", *addrPattern))
-	if err != nil {
-		log.Fatalf("error in --addr-rx: %v", err)
-	}
-
-	server := &smtpd.Server{
-		Hostname:         *hostname,
-		RecipientChecker: checkRecipient,
-		Handler:          handleMessage,
-		//ProtocolLogger:   log.New(os.Stderr, "smtp: ", 0),
-	}
-
-	if err := server.ListenAndServe(fmt.Sprintf(":%d", *port)); err != nil {
-		log.Fatal(err)
-	}
-}