Use this documentation with care! It describes
the heavily outdated version 5, which was actively
developed around 2010 and is considered dead by the
rsyslog team for many years now.
This documentation reflects the latest update of the
previously existing (now removed) v5-stable branch. It describes the 5.10.2 version, which was never
released. As such, it contains some content that
does not apply to any released version.
To obtain the doc that properly matches your installed
v5 version, obtain the doc set from your distro. Each
version of rsyslog contained the version that exactly
matches it.
As general advise, it is strongly suggested to
upgrade to the current version supported by the rsyslog
project. The current version can always be found on
the right-hand side info box on the rsyslog web site.
Note that there is no rsyslog community support available
for this heavily outdated version. If you need to stick
with it, please ask your distribution for support.
Sample Use Case: Single Central Log Server¶
We have a quite simple use case. There is one central syslog server, named central.example.net. These server is being reported to by two Linux machines with name zuse.example.net and turing.example.net. Also, there is a third client - ada.example.net - which send both its own messages to the central server but also forwards messages receive from an UDP-only capable router. We hav decided to use ada.example.net because it is in the same local network segment as the router and so we enjoy TLS’ security benefits for forwarding the router messages inside the corporate network. All systems (except the router) use rsyslog as the syslog software.

Please note that the CA must not necessarily be connected to the rest of the network. Actually, it may be considered a security plus if it is not. If the CA is reachable via the regular network, it should be sufficiently secured (firewal rules et al). Keep in mind that if the CA’s security is breached, your overall system security is breached.
In case the CA is compromised, you need to regenerate the CA’s certificate as well as all individual machines certificates.