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syslog-ng Premium Edition 7.0.19 - Release Notes

Secure logging using TLS

The syslog-ng application can send and receive log messages securely over the network using the Transport Layer Security (TLS) protocol using the network() and syslog() drivers.


This chapter describes how to use TLS encryption when using the standard syslog protocols, that is, the network() and syslog() drivers, for example, to forward log messages between two syslog-ng nodes, or to send log data to syslog-ng Store Box or another log server. Other destinations that support TLS-encryption are not discussed in this chapter (for example, http()).

TLS uses certificates to authenticate and encrypt the communication, as illustrated on the following figure:

Figure 7: Certificate-based authentication

The client authenticates the server by requesting its certificate and public key. Optionally, the server can also request a certificate from the client, thus mutual authentication is also possible.

In order to use TLS encryption in syslog-ng, the following elements are required:

  • A certificate on the syslog-ng server that identifies the syslog-ng server.

  • The certificate of the Certificate Authority that issued the certificate of the syslog-ng server (or the self-signed certificate of the syslog-ng server) must be available on the syslog-ng client.

When using mutual authentication to verify the identity of the clients, the following elements are required:

  • A certificate must be available on the syslog-ng client. This certificate identifies the syslog-ng client.

  • The certificate of the Certificate Authority that issued the certificate of the syslog-ng client must be available on the syslog-ng server.

Mutual authentication ensures that the syslog-ng server accepts log messages only from authorized clients.

For more information about configuring TLS communication in syslog-ng, see Encrypting log messages with TLS.

For more information about TLS-related error messages, see Error messages.

Supported OpenSSL versions

The following list contains information about the supported OpenSSL versions in each syslog-ng PE application version.

Linux glibc 2.11

syslog-ng PE version supported Open SSL version
7.0.1 OpenSSL 1.0.2j
7.0.2 OpenSSL 1.0.2j
7.0.3 OpenSSL 1.0.2j
7.0.4 OpenSSL 1.0.2j
7.0.5 OpenSSL 1.0.2j
7.0.6 OpenSSL 1.0.2m
7.0.7 OpenSSL 1.0.2m
7.0.8 OpenSSL 1.0.2m
7.0.9 OpenSSL 1.0.2o
7.0.10 OpenSSL 1.0.2o
7.0.11 OpenSSL 1.0.2p
7.0.12 OpenSSL 1.0.2q
7.0.13 OpenSSL 1.0.2q
7.0.14 OpenSSL 1.0.2r
7.0.15 OpenSSL 1.0.2s
7.0.16 OpenSSL 1.0.2s
7.0.17 OpenSSL 1.0.2t
7.0.18 OpenSSL 1.0.2t
7.0.19 OpenSSL 1.1.1d

Ubuntu Bionic

NOTE: The earliest version of syslog-ng PE that supports OpenSSL for Ubuntu Bionic is version 7.0.12.

syslog-ng PE version supported OpenSSL version
7.0.12 OpenSSL 1.1.0j
7.0.13 OpenSSL 1.1.0j
7.0.14 OpenSSL 1.1.0j
7.0.15 OpenSSL 1.1.0j
7.0.16 OpenSSL 1.1.0k
7.0.17 OpenSSL 1.1.0l
7.0.18 OpenSSL 1.1.0l
7.0.19 OpenSSL 1.1.1d
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