syslog-ng Open Source Edition 3.18 - Administration Guide

Copy the CA certificate (for example cacert.pem) of the Certificate Authority that issued the certificate of the syslog-ng server (or the self-signed certificate of the syslog-ng server) to the syslog-ng client hosts, for example into the /opt/syslog-ng/etc/syslog-ng/ca.d directory.

Issue the following command on the certificate: openssl x509 -noout -hash -in cacert.pem The result is a hash (for example 6d2962a8), a series of alphanumeric characters based on the Distinguished Name of the certificate.

Issue the following command to create a symbolic link to the certificate that uses the hash returned by the previous command and the .0 suffix.

ln -s cacert.pem 6d2962a8.0

Add a destination statement to the syslog-ng configuration file that uses the tls( ca-dir(path_to_ca_directory) ) option and specify the directory using the CA certificate. The destination must use the network() or the syslog() destination driver, and the IP address and port parameters of the driver must point to the syslog-ng server.

destination demo_tls_destination {
    network("10.1.2.3" port(6514)
        transport("tls")
        tls( ca-dir("/opt/syslog-ng/etc/syslog-ng/ca.d"))
    );
};

destination demo_tls_syslog_destination {
    syslog("10.1.2.3" port(6514)
                        transport("tls")
        tls(ca-dir("/opt/syslog-ng/etc/syslog-ng/ca.d"))
    );
};

Include the destination created in Step 2 in a log statement.

Create an X.509 certificate for the syslog-ng server.

Copy the certificate (for example syslog-ng.cert) of the syslog-ng server to the syslog-ng server host, for example into the /opt/syslog-ng/etc/syslog-ng/cert.d directory. The certificate must be a valid X.509 certificate in PEM format.

Copy the private key (for example syslog-ng.key) matching the certificate of the syslog-ng server to the syslog-ng server host, for example into the /opt/syslog-ng/etc/syslog-ng/key.d directory. The key must be in PEM format. If you want to use a password-protected key, see Password-protected keys.

Add a source statement to the syslog-ng configuration file that uses the tls( key-file(key_file_fullpathname) cert-file(cert_file_fullpathname) ) option and specify the key and certificate files. The source must use the source driver (network() or syslog()) matching the destination driver used by the syslog-ng client.

source demo_tls_source {
    network(ip(0.0.0.0) port(1999)
        transport("tls")
        tls( 
            key-file("/opt/syslog-ng/etc/syslog-ng/key.d/syslog-ng.key")
            cert-file("/opt/syslog-ng/etc/syslog-ng/cert.d/syslog-ng.cert")
        )
    );
};

source demo_tls_syslog_source {
    syslog(ip(0.0.0.0) port(1999)
    transport("tls")
    tls(
        key-file("/opt/syslog-ng/etc/syslog-ng/key.d/syslog-ng.key")
        cert-file("/opt/syslog-ng/etc/syslog-ng/cert.d/syslog-ng.cert")
        )
    );
};

Disable mutual authentication for the source by setting the following TLS option in the source statement: tls( peer-verify(optional-untrusted);

If you want to authenticate the clients, you have to configure mutual authentication. For details, see Mutual authentication using TLS.

For the details of the available tls() options, see TLS options.

source demo_tls_source {
    network(
        ip(0.0.0.0) port(1999)
        transport("tls")
        tls(
            key-file("/opt/syslog-ng/etc/syslog-ng/key.d/syslog-ng.key")
            cert-file("/opt/syslog-ng/etc/syslog-ng/cert.d/syslog-ng.cert")
            peer-verify(optional-untrusted)
        )
    );
};

source demo_tls_syslog_source {
    syslog(
        ip(0.0.0.0) port(1999)
        transport("tls")
        tls(
            key-file("/opt/syslog-ng/etc/syslog-ng/key.d/syslog-ng.key")
            cert-file("/opt/syslog-ng/etc/syslog-ng/cert.d/syslog-ng.cert")
            peer-verify(optional-untrusted)
        )
    );
};