Category Archives: Syslog

Basic Syslog messages, daemons, analyses, etc.

Meinberg LTOS: “syslog-ng” and the Observed Implementation Pitfalls

Meinberg, with the great help of Mr Weber, has implemented “syslog over TLS” in the LTOS version 7.06. The following report describes the general advantages of “syslog over TLS” and the implementation of it in the LTOS.

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Palo Alto Syslog via TLS

As we have just set up a TLS capable syslog server, let’s configure a Palo Alto Networks firewall to send syslog messages via an encrypted channel. While it was quite straightforward to configure I ran into a couple of (unresolved) problems as I added and deleted some syslog servers and their certificates. Uhm.

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syslog-ng with TLS: Installation Guide

Some years ago I wrote a blog post called “Basic syslog-ng Installation“. While I used it myself quite often in my labs or at the customers’ sites, it shows only basic UDP transport which is both unreliable and insecure. So, let’s have a look at a fresh installation of syslog-ng with TLS support for security reasons. However, TCP and UDP as transport are covered as well for the support of legacy systems.

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Counting NTP Clients

Wherever you’re running an NTP server: It is really interesting to see how many clients are using it. Either at home, in your company or worldwide at the NTP Pool Project. The problem is that ntp itself does not give you this answer of how many clients it serves. There are the “monstats” and “mrulist” queries but they are not reliable at all since they are not made for this. Hence I had to take another path in order to count NTP clients for my stratum 1 NTP servers. Let’s dig in:

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Logfile Parsing

While parsing logfiles on a Linux machine, several commands are useful in order to get the appropriate results, e.g., searching for concrete events in firewall logs.

In this post, I list a few standard parsing commands such as grep, sort, uniq, or wc. Furthermore, I present a few examples of these small tools. However, it’s all about try and error when building large command pipes. ;)

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Grep Commands for Cisco ASA Syslog Messages

In a basic environment with a Cisco ASA firewall I am logging everything to a syslog-ng server. As there aren’t any reporting tools installed, I am using grep to filter the huge amount of syslog messages in order to get the information I want to know. In this blog post I list a few greps for getting the interesting data.

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Basic syslog-ng Installation

This post shows a guideline for a basic installation of the open source syslog-ng daemon in order to store syslog messages from various devices in a separate file for each device.

I am using such an installation for my firewalls, routers, etc., to have an archive with all of its messages. Later on, I can grep through these logfiles and search for specific events. Of course it does not provide any built-in filter or correlation features – it is obviously not a SIEM. However, as a first step it’s better than nothing. ;)

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