diff --git a/installer.cfg b/installer.cfg
index 8d0f255..77e75eb 100644
--- a/installer.cfg
+++ b/installer.cfg
@@ -1,7 +1,3 @@
-[general]
-tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
-tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
-
 [database]
 # Select database engine : postgres or mysql
 engine = postgres
diff --git a/modoboa_installer/scripts/amavis.py b/modoboa_installer/scripts/amavis.py
index 0d6dea1..272816a 100644
--- a/modoboa_installer/scripts/amavis.py
+++ b/modoboa_installer/scripts/amavis.py
@@ -25,6 +25,12 @@ class Amavis(base.Installer):
             return "/etc/amavisd"
         return "/etc/amavis"
 
+    def get_daemon_name(self):
+        """Return appropriate daemon name."""
+        if package.backend.FORMAT == "rpm":
+            return "amavisd"
+        return "amavis"
+
     def get_config_files(self):
         """Return appropriate config files."""
         if package.backend.FORMAT == "deb":
diff --git a/modoboa_installer/scripts/clamav.py b/modoboa_installer/scripts/clamav.py
index 38c906e..c1d3283 100644
--- a/modoboa_installer/scripts/clamav.py
+++ b/modoboa_installer/scripts/clamav.py
@@ -12,7 +12,6 @@ class Clamav(base.Installer):
     """ClamAV installer."""
 
     appname = "clamav"
-    daemon_name = "clamav-daemon"
     packages = {
         "deb": ["clamav-daemon"],
         "rpm": [
@@ -55,17 +54,23 @@ class Clamav(base.Installer):
             user = "clamupdate"
             utils.exec_cmd(
                 "perl -pi -e 's/^Example/#Example/' /etc/freshclam.conf")
-            utils.exec_cmd(
-                """cat <<EOM >> /usr/lib/systemd/system/clamd@.service
+            # Check if not present before
+            path = "/usr/lib/systemd/system/clamd@.service"
+            code, output = utils.exec_cmd(
+                "grep 'WantedBy=multi-user.target' {}".format(path))
+            if code:
+                utils.exec_cmd(
+                    """cat <<EOM >> {}
+
 [Install]
 WantedBy=multi-user.target
 EOM
-""")
+""".format(path))
 
-        if utils.dist_name == "ubuntu":
+        if utils.dist_name() == "ubuntu":
             # Stop freshclam daemon to allow manual download
             utils.exec_cmd("service clamav-freshclam stop")
             utils.exec_cmd("freshclam", sudo_user=user)
             utils.exec_cmd("service clamav-freshclam start")
         else:
-            utils.exec_cmd("freshclam", sudo_user=user)
+            utils.exec_cmd("freshclam", sudo_user=user, login=False)
diff --git a/modoboa_installer/scripts/dovecot.py b/modoboa_installer/scripts/dovecot.py
index e1df7fb..f753b24 100644
--- a/modoboa_installer/scripts/dovecot.py
+++ b/modoboa_installer/scripts/dovecot.py
@@ -52,6 +52,14 @@ class Dovecot(base.Installer):
         """Additional variables."""
         context = super(Dovecot, self).get_template_context()
         pw = pwd.getpwnam(self.user)
+        if "centos" in utils.dist_name():
+            protocols = "protocols = imap lmtp sieve"
+            extra_protocols = self.config.get("dovecot", "extra_protocols")
+            if extra_protocols:
+                protocols += " {}".format(extra_protocols)
+        else:
+            # Protocols are automatically guessed on debian/ubuntu
+            protocols = ""
         context.update({
             "db_driver": self.db_driver,
             "mailboxes_owner_uid": pw[2],
@@ -59,6 +67,7 @@ class Dovecot(base.Installer):
             "modoboa_dbname": self.config.get("modoboa", "dbname"),
             "modoboa_dbuser": self.config.get("modoboa", "dbuser"),
             "modoboa_dbpassword": self.config.get("modoboa", "dbpassword"),
+            "protocols": protocols
         })
         return context
 
diff --git a/modoboa_installer/scripts/files/dovecot/dovecot.conf.tpl b/modoboa_installer/scripts/files/dovecot/dovecot.conf.tpl
index e72d94e..0ebb94b 100644
--- a/modoboa_installer/scripts/files/dovecot/dovecot.conf.tpl
+++ b/modoboa_installer/scripts/files/dovecot/dovecot.conf.tpl
@@ -18,6 +18,7 @@
 
 # Enable installed protocols
 !include_try /usr/share/dovecot/protocols.d/*.protocol
+%protocols
 
 # A comma separated list of IPs or hosts where to listen in for connections. 
 # "*" listens in all IPv4 interfaces, "::" listens in all IPv6 interfaces.
diff --git a/modoboa_installer/scripts/files/uwsgi/uwsgi.ini.tpl b/modoboa_installer/scripts/files/uwsgi/uwsgi.ini.tpl
index 87e06c2..a013085 100644
--- a/modoboa_installer/scripts/files/uwsgi/uwsgi.ini.tpl
+++ b/modoboa_installer/scripts/files/uwsgi/uwsgi.ini.tpl
@@ -6,8 +6,9 @@ home = %modoboa_venv_path
 chdir = %modoboa_instance_path
 module = instance.wsgi:application
 master = true
-harakiri = 60
 processes = %nb_processes
 vhost = true
 no-default-app = true
-socket = %uwsgi_socket_path
\ No newline at end of file
+socket = %uwsgi_socket_path
+chmod-socket = 660
+vacuum = true
diff --git a/modoboa_installer/scripts/modoboa.py b/modoboa_installer/scripts/modoboa.py
index 2d9d508..85244e1 100644
--- a/modoboa_installer/scripts/modoboa.py
+++ b/modoboa_installer/scripts/modoboa.py
@@ -108,7 +108,7 @@ class Modoboa(base.Installer):
         context.update({
             "dovecot_mailboxes_owner": (
                 self.config.get("dovecot", "mailboxes_owner")),
-            "radicale_enabled": "#" if "modoboa-radicale" in extensions else ""
+            "radicale_enabled": "" if "modoboa-radicale" in extensions else "#"
         })
         return context
 
@@ -128,6 +128,9 @@ class Modoboa(base.Installer):
             "modoboa_stats.RRD_ROOTDIR": rrd_root_dir,
             "modoboa_pdfcredentials.STORAGE_DIR": pdf_storage_dir,
         }
+        for path in ["/var/log/maillog", "/var/log/mail.log"]:
+            if os.path.exists(path):
+                settings["modoboa_stats.LOGFILE"] = path
 
         for name, value in settings.items():
             query = (
diff --git a/modoboa_installer/scripts/nginx.py b/modoboa_installer/scripts/nginx.py
index b1d0ae0..40ccb32 100644
--- a/modoboa_installer/scripts/nginx.py
+++ b/modoboa_installer/scripts/nginx.py
@@ -44,11 +44,12 @@ class Nginx(base.Installer):
             if os.path.exists(link):
                 return
             os.symlink(dst, link)
-            group = "www-data"
+            group = self.config.get("modoboa", "user")
+            user = "www-data"
         else:
             dst = os.path.join(
                 self.config_dir, "conf.d", "{}.conf".format(hostname))
             utils.copy_from_template(src, dst, context)
-            group = "nginx"
-        system.add_user_to_group(
-            group, self.config.get("modoboa", "user"))
+            group = "uwsgi"
+            user = "nginx"
+        system.add_user_to_group(user, group)
diff --git a/modoboa_installer/scripts/postfix.py b/modoboa_installer/scripts/postfix.py
index 890c83b..73b6b02 100644
--- a/modoboa_installer/scripts/postfix.py
+++ b/modoboa_installer/scripts/postfix.py
@@ -1,5 +1,9 @@
 """Postfix related tools."""
 
+try:
+    import configparser
+except ImportError:
+    import ConfigParser as configparser
 import os
 
 from .. import package
@@ -29,6 +33,17 @@ class Postfix(base.Installer):
 
     def install_packages(self):
         """Preconfigure postfix package installation."""
+        if "centos" in utils.dist_name():
+            config = configparser.SafeConfigParser()
+            with open("/etc/yum.repos.d/CentOS-Base.repo") as fp:
+                config.readfp(fp)
+            config.set("centosplus", "enabled", "1")
+            config.set("centosplus", "includepkgs", "postfix-*")
+            config.set("base", "exclude", "postfix-*")
+            config.set("updates", "exclude", "postfix-*")
+            with open("/etc/yum.repos.d/CentOS-Base.repo", "w") as fp:
+                config.write(fp)
+
         package.backend.preconfigure(
             "postfix", "main_mailer_type", "select", "No configuration")
         super(Postfix, self).install_packages()
@@ -71,6 +86,16 @@ class Postfix(base.Installer):
                     " ".join(extensions), db_url, self.config_dir))
         utils.exec_cmd(cmd)
 
+        # Check chroot directory
+        chroot_dir = "/var/spool/postfix/etc"
+        chroot_files = ["services", "resolv.conf"]
+        if not os.path.exists(chroot_dir):
+            os.mkdir(chroot_dir)
+        for f in chroot_files:
+            path = os.path.join(chroot_dir, f)
+            if not os.path.exists(path):
+                utils.copy_file(os.path.join("/etc", f), path)
+
         # Generate EDH parameters
         if not os.path.exists("{}/dh2048.pem".format(self.config_dir)):
             cmd = "openssl dhparam -out dh2048.pem 2048"
diff --git a/modoboa_installer/scripts/razor.py b/modoboa_installer/scripts/razor.py
index 06b1426..7f5f965 100644
--- a/modoboa_installer/scripts/razor.py
+++ b/modoboa_installer/scripts/razor.py
@@ -36,7 +36,7 @@ class Razor(base.Installer):
         utils.copy_file(
             os.path.join(path, "razor-agent.conf"), self.config_dir)
         utils.exec_cmd("razor-admin -home {} -discover".format(path),
-                       sudo_user=user)
+                       sudo_user=user, login=False)
         utils.exec_cmd("razor-admin -home {} -register".format(path),
-                       sudo_user=user)
+                       sudo_user=user, login=False)
         # FIXME: move log file to /var/log ?
diff --git a/modoboa_installer/scripts/spamassassin.py b/modoboa_installer/scripts/spamassassin.py
index a510170..8f44877 100644
--- a/modoboa_installer/scripts/spamassassin.py
+++ b/modoboa_installer/scripts/spamassassin.py
@@ -55,5 +55,7 @@ class Spamassassin(base.Installer):
     def post_run(self):
         """Additional tasks."""
         utils.exec_cmd(
-            "pyzor discover", sudo_user=self.config.get("amavis", "user"))
+            "pyzor discover", sudo_user=self.config.get("amavis", "user"),
+            login=False
+        )
         install("razor", self.config)
diff --git a/modoboa_installer/scripts/uwsgi.py b/modoboa_installer/scripts/uwsgi.py
index 8e00cd4..4da9c1a 100644
--- a/modoboa_installer/scripts/uwsgi.py
+++ b/modoboa_installer/scripts/uwsgi.py
@@ -34,7 +34,7 @@ class Uwsgi(base.Installer):
             "modoboa_venv_path": self.config.get("modoboa", "venv_path"),
             "modoboa_instance_path": (
                 self.config.get("modoboa", "instance_path")),
-            "uwsgi_socket_path": self.socket_path
+            "uwsgi_socket_path": self.socket_path,
         })
         return context
 
@@ -58,9 +58,11 @@ class Uwsgi(base.Installer):
             os.symlink(dst, link)
         else:
             system.add_user_to_group(
-                "uwsgi", self.config.get("modoboa", "user"))
+                self.config.get("modoboa", "user"), "uwsgi")
+            utils.exec_cmd("chmod -R g+w {}/media".format(
+                self.config.get("modoboa", "instance_path")))
             pattern = (
-                "s/emperor-tyrant = true/emperor-tyrant false/")
+                "s/emperor-tyrant = true/emperor-tyrant = false/")
             utils.exec_cmd(
                 "perl -pi -e '{}' /etc/uwsgi.ini".format(pattern))
 
diff --git a/modoboa_installer/ssl.py b/modoboa_installer/ssl.py
new file mode 100644
index 0000000..3b996b9
--- /dev/null
+++ b/modoboa_installer/ssl.py
@@ -0,0 +1,49 @@
+"""SSL tools."""
+
+import os
+
+from . import utils
+
+
+class CertificateBackend(object):
+    """Base class."""
+
+    def __init__(self, config):
+        """Set path to certificates."""
+        self.config = config
+        for base_dir in ["/etc/pki/tls", "/etc/ssl"]:
+            if os.path.exists(base_dir):
+                self.config.set(
+                    "general", "tls_key_file",
+                    "{}/private/%(hostname)s.key".format(base_dir))
+                self.config.set(
+                    "general", "tls_cert_file",
+                    "{}/certs/%(hostname)s.cert".format(base_dir))
+                return
+        raise RuntimeError("Cannot find a directory to store certificate")
+
+
+class SelfSignedCertificate(CertificateBackend):
+    """Create a self signed certificate."""
+
+    def create(self):
+        """Create a certificate."""
+        if os.path.exists(self.config.get("general", "tls_key_file")):
+            answer = utils.user_input(
+                "Overwrite the existing SSL certificate? (y/N) ")
+            if not answer.lower().startswith("y"):
+                return
+        utils.printcolor(
+            "Generating new self-signed certificate", utils.YELLOW)
+        utils.exec_cmd(
+            "openssl req -new -newkey rsa:4096 -days 365 -nodes -x509 "
+            "-subj '/CN={}' -keyout {} -out {}".format(
+                self.config.get("general", "hostname"),
+                self.config.get("general", "tls_key_file"),
+                self.config.get("general", "tls_cert_file"))
+        )
+
+
+def get_backend(config):
+    """Return the appropriate backend."""
+    return SelfSignedCertificate(config)
diff --git a/modoboa_installer/utils.py b/modoboa_installer/utils.py
index bc790a8..0550f5e 100644
--- a/modoboa_installer/utils.py
+++ b/modoboa_installer/utils.py
@@ -33,7 +33,7 @@ def user_input(message):
     return answer
 
 
-def exec_cmd(cmd, sudo_user=None, pinput=None, **kwargs):
+def exec_cmd(cmd, sudo_user=None, pinput=None, login=True, **kwargs):
     """Execute a shell command.
     Run a command using the current user. Set :keyword:`sudo_user` if
     you need different privileges.
@@ -45,7 +45,7 @@ def exec_cmd(cmd, sudo_user=None, pinput=None, **kwargs):
     """
     sudo_user = ENV.get("sudo_user", sudo_user)
     if sudo_user is not None:
-        cmd = "sudo -i -u %s %s" % (sudo_user, cmd)
+        cmd = "sudo {}-u {} {}".format("-i " if login else "", sudo_user, cmd)
     if "shell" not in kwargs:
         kwargs["shell"] = True
     if pinput is not None:
diff --git a/run.py b/run.py
index 191ec10..756cc30 100755
--- a/run.py
+++ b/run.py
@@ -11,6 +11,7 @@ except ImportError:
 from modoboa_installer import scripts
 from modoboa_installer import utils
 from modoboa_installer import package
+from modoboa_installer import ssl
 
 
 def main():
@@ -30,6 +31,8 @@ def main():
     config = configparser.SafeConfigParser()
     with open("installer.cfg") as fp:
         config.readfp(fp)
+    if not config.has_section("general"):
+        config.add_section("general")
     config.set("general", "hostname", args.hostname)
     utils.printcolor(
         "Your mail server {} will be installed with the following components:"
@@ -52,6 +55,7 @@ def main():
         "and come back later ;)", utils.BLUE)
     utils.printcolor("Starting...", utils.GREEN)
     package.backend.install("sudo")
+    ssl.get_backend(config).create()
     scripts.install("modoboa", config)
     scripts.install("postfix", config)
     scripts.install("amavis", config)