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iRedMail generates a self-signed SSL certificate during installation, it's
fine if you just want to secure the network connections (POP3/IMAP/SMTP over
TLS, HTTPS), but mail clients or web browsers will promot a annoying message
to warn you this self-signed certificate is not trusted. To avoid this
annoying message, you have to buy a SSL certificate from SSL certificate
provider. Search buy ssl certificate
in Google will give you many SSL
providers, choose the one you prefer.
"Let's Encrypt" offers free SSL certificate, please follow its official tutorial to get one: https://certbot.eff.org
Attention
The --apache
option of certbot
program will modify Apache config
files, most time it messes up iRedMail configurations, so it's better
to get the cert with certonly --webroot
option while requesting cert, then
follow tutorial below to update config files to use the cert.
To buy ssl cert from a trusted vendor, you need to generate a new SSL
key and signing request file on your server with openssl
command:
Warning
Do NOT use key length smaller than 2048
bit, it's insecure.
# openssl req -new -newkey rsa:2048 -nodes -keyout privkey.pem -out server.csr
This command will generate two files:
privkey.pem
: the private key for the decryption of your SSL certificate.server.csr
: the certificate signing request (CSR) file used to apply
for your SSL certificate. This file is required by SSL certificate
provider.The openssl command will prompt for the following X.509 attributes of the certificate:
Country Name (2 letter code)
: Use the two-letter code without punctuation
for country. for example: US, CA, CN.State or Province Name (full name)
: Spell out the state completely; do not
abbreviate the state or province name, for example: California.Locality Name (eg, city)
: City or town name, for example: Berkeley.Organization Name (eg, company)
: Your company name.Organizational Unit Name (eg, section)
: The name of the department or
organization unit making the request.Common Name (e.g. server FQDN or YOUR name)
: server FQDN or your name.Email Address []
: your full email address.A challenge password []
: type a password for this ssl certificate.An optional company name []
: an optional company name.NOTE: Some certificates can only be used on web servers using the Common Name
specified during enrollment. For example, a certificate for the domain
domain.com
will receive a warning if accessing a site named www.domain.com
or secure.domain.com
, because www.domain.com
and secure.domain.com
are
different from domain.com
.
Now you have two files: privkey.pem
and server.csr
. Go to the website of
your preferred SSL privider, it will ask you to upload server.csr
file to
issue an SSL certificate.
Usually, SSL provider will give you 2 files:
server.ca-bundle
)We need above 2 files, and privkey.pem
. Upload them to your server, you can
store them in any directory you like, recommended directories are:
cert.pem
and fullchain.pem
should be placed under
/etc/pki/tls/certs/
, privkey.pem
should be /etc/pki/tls/private/
.cert.pem
and fullchain.pem
should be
placed under /etc/ssl/certs/
, privkey.pem
should be /etc/ssl/private/
./etc/ssl/
.We use CentOS for example in below tutorial, please adjust the file to correct one on your server according to above description.
We can use postconf
command to update SSL related settings directly:
postconf -e smtpd_tls_cert_file='/etc/pki/tls/certs/cert.pem'
postconf -e smtpd_tls_key_file='/etc/pki/tls/private/privkey.pem'
postconf -e smtpd_tls_CAfile='/etc/pki/tls/certs/fullchain.pem'
Restarting Postfix service is required.
SSL certificate settings are defined in Dovecot main config file,
/etc/dovecot/dovecot.conf
(Linux/OpenBSD) or
/usr/local/etc/dovecot/dovecot.conf
(FreeBSD):
ssl = required
ssl_cert = </etc/pki/tls/certs/cert.pem
ssl_key = </etc/pki/tls/private/privkey.pem
ssl_ca = </etc/pki/tls/certs/fullchain.pem
Restarting Dovecot service is required.
/etc/httpd/conf.d/ssl.conf
./etc/apache2/sites-available/default-ssl
(or default-ssl.conf
)/usr/local/etc/apache24/extra/httpd-ssl.conf
. Note:
if you're running different version of Apache, the path will be slightly
different (apache24
will be apache[_version_]
)./var/www/conf/httpd.conf
. Note: OpenBSD 5.6 and later releases don't
ship Apache anymore.Example:
SSLCertificateFile /etc/pki/tls/certs/cert.pem
SSLCertificateKeyFile /etc/pki/tls/private/privkey.pem
SSLCertificateChainFile /etc/pki/tls/certs/fullchain.pem
Restarting Apache service is required.
/etc/nginx/templates/ssl.tmpl
(or /etc/nginx/conf.d/default.conf
on old iRedMail release)/usr/local/etc/nginx/templates/ssl.tmpl
(or /usr/local/etc/nginx/conf.d/default.conf
on old iRedMail release)server {
listen 443;
...
ssl on;
ssl_certificate /etc/pki/tls/certs/cert.pem;
ssl_certificate_key /etc/pki/tls/private/privkey.pem;
...
}
Some browsers may complain about a certificate signed by a well-known certificate authority, while other browsers may accept the certificate without issues. This occurs because the issuing authority has signed the server certificate using an intermediate certificate that is not present in the certificate base of well-known trusted certificate authorities which is distributed with a particular browser. In this case the authority provides a bundle of chained certificates which should be concatenated to the signed server certificate. The server certificate must appear before the chained certificates in the combined file:
# cd /etc/pki/tls/certs/
# cat cert.pem fullchain.pem > server.chained.crt
Then update ssl_certificate
parameter in /etc/nginx/conf.d/default.conf
:
ssl_certificate /etc/pki/tls/certs/server.chained.crt;
Restarting Nginx service is required.
If MySQL/MariaDB is listening on localhost and not accessible from external network, this is OPTIONAL.
/etc/my.cnf
/etc/mysql/my.cnf
./etc/mysql/mariadb.conf.d/mysqld.cnf
./usr/local/etc/my.cnf
./etc/my.cnf
.[mysqld]
ssl-ca = /etc/pki/tls/certs/fullchain.pem
ssl-cert = /etc/pki/tls/certs/cert.pem
ssl-key = /etc/pki/tls/private/privkey.pem
If OpenLDAP is listening on localhost and not accessible from external network, this is OPTIONAL.
/etc/openldap/slapd.conf
./etc/ldap/slapd.conf
./usr/local/etc/openldap/slapd.conf
./etc/openldap/slapd.conf
.TLSCACertificateFile /etc/pki/tls/certs/fullchain.pem
TLSCertificateFile /etc/pki/tls/certs/cert.pem
TLSCertificateKeyFile /etc/pki/tls/private/privkey.pem
Restarting OpenLDAP service is required.
If you want to connect with TLS (port 389) or SSL (port 636) for secure
connection from command line tools like ldapsearch
, please update parameter
TLS_CACERT
in OpenLDAP client config file also, otherwise you will get
error message like Peer's Certificate issuer is not recognized
.
/etc/openldap/ldap.conf
./etc/ldap/ldap.conf
./usr/local/etc/openldap/ldap.conf
./etc/openldap/ldap.conf
.TLS_CACERT /etc/pki/tls/certs/fullchain.pem
To connect with TLS, please run ldapsearch
with argument -Z
and use
ldap://<your_server_name>:389
as ldap host. For example:
ldapsearch -x -W -Z \
-H 'ldap://mail.example.com:389' \
-D 'cn=vmail,dc=example,dc=com' \
-b 'o=domains,dc=example,dc=com' mail
ldaps://<your_server_name>:636
as ldap host.
for example:ldapsearch -x -W \
-H 'ldaps://mail.example.com:636' \
-D 'cn=vmail,dc=example,dc=com' \
-b 'o=domains,dc=example,dc=com' mail
If ldapd(8) is listening on localhost and not accessible from external network, this is OPTIONAL.
For more details about ldapd config file, please check its manual page: ldapd.conf(5).
To make ldapd(8) listening on network interface for external network, please
make sure you have setting in /etc/ldapd.conf
to listen on the interface. We
use em0
as external network interface here for example.
# Listen on network interface 'em0', port 389, use STARTTLS for secure connection.
listen on em0 port 389 tls
If you want to use port 636 with SSL, try this:
# Listen on network interface 'em0', port 636, use SSL for secure connection.
listen on em0 port 636 ldaps
ldapd(8) will look for SSL cert and key from directory /etc/ldap/certs/
by
default, the cert file name is <interface_name>.crt
and <interface_name>.key
.
In our case, it will look for /etc/ldap/certs/em0.crt
and /etc/ldap/certs/em0.key
.
Since iRedMail already generates a cert and key, we can use it directly. If you have bought SSL cert/key, or requested one from LetsEncrypt, you can use them too.
cd /etc/ldap/certs/
ln -s /etc/ssl/iRedMail.crt em0.crt
ln -s /etc/ssl/iRedMail.key em0.key
Now restart ldapd(8) service:
rcctl restart ldapd