diff --git a/launcher b/launcher
index bcf6a81..bc1c994 100755
--- a/launcher
+++ b/launcher
@@ -9,6 +9,7 @@ local_image=local_seafile/server:latest
 dockerdir=$(cd "$(dirname $0)"; pwd -P)
 sharedir=$dockerdir/shared
 installdir=/opt/seafile/seafile-server-$version
+bootstrap_conf=$dockerdir/bootstrap/bootstrap.conf
 
 cd $dockerdir
 
@@ -37,8 +38,11 @@ init_shared() {
 }
 
 set_ports() {
-    ports="-p 80:80 -p 443:443"
-    ports=""
+    ports=$(docker run --rm -it \
+                   -v ${dockerdir}/scripts:/scripts \
+                   -v ${dockerdir}/bootstrap:/bootstrap:ro \
+                   $image \
+                   /scripts/bootstrap.py --parse-ports)
 }
 
 set_bootstrap_volumes() {
@@ -80,7 +84,6 @@ set_volumes() {
 }
 
 bootstrap() {
-    local bootstrap_conf=$dockerdir/bootstrap/bootstrap.conf
     if [[ ! -e $bootstrap_conf  ]]; then
         err_and_quit "The file $bootstrap_conf doesn't exist. Have you run seafile-server-setup?"
     fi
diff --git a/samples/server.conf b/samples/server.conf
index 00a21dc..e64be3d 100644
--- a/samples/server.conf
+++ b/samples/server.conf
@@ -1,5 +1,7 @@
+# If you edit this file, remember to run ./launcher rebuild
 [server]
 server.hostname = seafile.example.com
 server.https = true
 admin.email = me@example.com
-admin.password = asecret
\ No newline at end of file
+admin.password = asecret
+server.port_mappings = 80:80,443:443
\ No newline at end of file
diff --git a/scripts/bootstrap.py b/scripts/bootstrap.py
index d7fe3ac..6912d34 100755
--- a/scripts/bootstrap.py
+++ b/scripts/bootstrap.py
@@ -7,6 +7,7 @@ setup-seafile.sh or setup-seafile-mysql.sh. It's supposed to run inside the
 container.
 """
 
+import argparse
 import os
 from os.path import abspath, basename, exists, dirname, join, isdir
 import shutil
@@ -56,7 +57,28 @@ def generate_local_dockerfile():
     }
     render_template('/templates/Dockerfile.template', join(generated_dir, 'Dockerfile'), context)
 
+def parse_args():
+    ap = argparse.ArgumentParser()
+    ap.add_argument('--parse-ports', action='store_true')
+
+    return ap.parse_args()
+
+def do_parse_ports():
+    """
+    Parse the server.port_mappings option and print docker command line port
+    mapping flags like "-p 80:80 -p 443:443"
+    """
+    # conf is like '80:80,443:443'
+    conf = get_conf('server.port_mappings', '').strip()
+    if conf:
+        sys.stdout.write(' '.join(['-p {}'.format(part.strip()) for part in conf.split(',')]))
+        sys.stdout.flush()
+
 def main():
+    args = parse_args()
+    if args.parse_ports:
+        do_parse_ports()
+        return
     if not exists(shared_seafiledir):
         os.mkdir(shared_seafiledir)
     if not exists(generated_dir):
@@ -92,4 +114,5 @@ def main():
             shutil.move(src, shared_seafiledir)
 
 if __name__ == '__main__':
+    # TODO: validate the content of bootstrap.conf is valid
     main()