Sending syslog messages from a Linux box to SIEM

Let’s imagine that we need to direct log messages from our Linux box to SIEM solution. For centralized management/backup or correlation purposes. How do we do that?

This article is about SuSE Linux or SLES, but it can be easily customized for other Linux flavors.

First of all, newer Linux distros use syslog-ng or syslog-new-generation. In SLES, we can find configuration files under “/etc/syslog-ng/” folder. Two of them:

First one, is the one we edit directly. We should not edit syslog-ng.conf directly. The changes made to get into syslog-ng.conf once we issue the SuSEconfig command. So the process is as follows.

We edit file to add these lines:

destination POP-W8 { udp( “10.x.y.124” port(514) ); };
destination SIEM { udp( “10.a.b.67” port(514) ); };

log { source(src); destination(POP-W8); destination(SIEM); };

With first two lines we define our targets. These can be another, non local, syslog server, or some SIEM solution. In this case, first line defines a syslog server installed on our PC, and the second line defines our SIEM solution. This way we can track messages on two places and see if there are any misses. The syntax is:

destination TARGETNAME { udp(“ADDRESS” port(PORT) ); };

I think everything is obvious.

The third line actually directs messages to defined destinations:

log { source(src); destination(POP-W8); destination(SIEM); };

So, what this line says is: log all messages defined by src to all listed targets. The src log source is predefined in SLES and means all local messages.

After we edited our “/etc/syslog-ng/” file, we need to execute:

SuSEconfig -module syslog-ng

so these changes get written to “/etc/syslog-ng/syslog-ng.conf“. Finally, we restart the syslog daemon:

/etc/init.d/syslog restart


Now we should start receiving messages on our defined targets.


Thanks for reading.



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