# openssl Network Stream Driver

Driver Name: | ossl
Author: | Andre Lorbach <alorbach@adiscon.com>
Available since: | 8.36.0

## Purpose

This network stream driver implements a TLS protected transport via the OpenSSL library.

## Supported Driver Modes

- 0 - unencrypted transmission (just like ptcp driver)
- 1 - TLS-protected operation

Note

Mode 0 does not provide any benefit over the ptcp driver. This mode exists for technical reasons, but should not be used. It may be removed in the future.

## Supported Authentication Modes

- anon - anonymous authentication as described in IETF’s draft-ietf-syslog-transport-tls-12 Internet draft
- x509/fingerprint - certificate fingerprint authentication as described in IETF’s draft-ietf-syslog-transport-tls-12 Internet draft. Even in x509/fingerprint mode, both the client and server certificate currently must be signed by the same root CA.
- x509/certvalid - certificate validation only. x509/certvalid is a nonstandard mode. It validates the remote peers certificate, but does not check the subject name. This is weak authentication that may be useful in scenarios where multiple devices are deployed and it is sufficient proof of authenticity when their certificates are signed by the CA the server trusts. This is better than anon authentication, but still not recommended. Known Problems
- x509/name - certificate validation and subject name authentication as described in IETF’s draft-ietf-syslog-transport-tls-12 Internet draft

Note

“anon” does not permit to authenticate the remote peer. As such, this mode is vulnerable to man in the middle attacks as well as unauthorized access. It is recommended NOT to use this mode. A certificate / key does not need to be configured in this authmode.

Note

Anon mode changes in: v8.190 (or above)

- Anonymous Ciphers (DH and ECDH) are available in ANON mode.
- Server does not require a certificate anymore in anon mode.
- If Server has a certificate and the Client does not, the highest possible ciphers will be selected.
- If both Server and Client do not have a certificate, the highest available anon cipher will be used.

See also

Help with configuring/using `Rsyslog`:

- Mailing list - best route for general questions
- GitHub: rsyslog source project - detailed questions, reporting issues that are believed to be bugs with `Rsyslog`
- Stack Exchange (View, Ask) - experimental support from rsyslog community

See also

Contributing to `Rsyslog`:

- Source project: rsyslog project README.
- Documentation: rsyslog-doc project README

Copyright 2008-2020 Rainer Gerhards (Großrinderfeld), and Others.