Web interfaces for your syslog server – an overview

This is the 2020 edition of my most read blog entry about syslog-ng web-based graphical user interfaces (web GUIs). Many things have changed in the past few years. In 2011, only a single logging as a service solution was available, while nowadays, I regularly run into others. Also, while some software disappeared, the number of logging-related GUIs is growing. This is why in this post, I will mostly focus on generic log management and open source instead of highly specialized software, like SIEMs.

Why grep is not enough?

Centralized event logging has been an important part of IT for many years for many reasons. Firstly, it is more convenient to browse logs in a central location rather than viewing them on individual machines. Secondly, central storage is also more secure. Even if logs stored locally are altered or removed, you can still check the logs on the central log server. Finally, compliance with different regulations also makes central logging necessary.

System administrators often prefer to use the command line. Utilities such as grep and AWK are powerful tools, but complex queries can be completed much faster with logs indexed in a database and a web interface. In the case of large amounts of messages, a web-based database solution is not just convenient, it is a necessity. With tens of thousands of incoming messages per second, the indexes of log databases still give Google-like response times even for the most complex queries, while traditional text-based tools are not able to scale as efficiently.

Why still syslog-ng?

Many software used for log analysis come with their own log aggregation agents. So why should you still use syslog-ng then? As organizations grow, so does the IT staff starts to diversify. Separate teams are created for operations, development and security, each with its own specialized needs in log analysis. And even the business side often needs log analysis as an input for business decisions. You can quickly end up with 4-5 different log analysis and aggregation systems running in parallel and working from the very same log messages.

This is where syslog-ng can come handy: creating a dedicated log management layer, where syslog-ng collects all of the log messages centrally, does initial basic log analysis, and feeds all the different log analysis software with relevant log messages. This can save you time and resources in multiple ways:

  • You only have to learn one tool instead of many.

  • Only a single tool to push through security and operations teams.

  • There are less computing resources on clients.

  • Logs travel only once over the network.

  • Long term archival in a single location with syslog-ng instead of using multiple log analysis software.

  • Filtering on the syslog-ng side can save significantly on the hardware costs of the log analysis software, and also on licensing in case of a commercial solution.

The syslog-ng application can collect both system and application logs, and can be installed both as a client and a server. Thus, you have a single application to install for log management everywhere on your network. It can reliably collect and transport huge amounts of log messages, parse (“look into”) your log messages, enrich them with geographical location and other extra data, making filters and thus, log routing, much more accurate.

Logging as a Service (LaaS)

A couple years ago, Loggly was the pioneer of logging as a service (LaaS). Today, there are many other LaaS providers (Papertrail, Logentries, Sumo Logic, and so on) and syslog-ng works perfectly with all of them.

Structured fields and name-value pairs in logs are increasingly important, as they are easier to search, and it is easier to create meaningful reports from them. The more recent IETF RFC 5424 syslog standard supports structured data, but it is still not in widespread use.

People started to use JSON embedded into legacy (RFC 3164) syslog messages. The syslog-ng application can send JSON-formatted messages – for example, you can convert the following messages into structured JSON messages:

  • RFC5424-formatted log messages.

  • Windows EventLog messages received from the syslog-ng Agent for Windows application.

  • Name-value pairs extracted from a log message with PatternDB or the CSV parser.

Loggly and other services can receive JSON-formatted messages, and make them conveniently available from the web interface.

A number of LaaS providers are already supported by syslog-ng out of the box. If your service of choice is not yet directly supported, the following blog can help you create a new LaaS destination: https://www.syslog-ng.com/community/b/blog/posts/how-to-use-syslog-ng-with-laas-and-why

Some non-syslog-ng-based solutions

Before focusing on the solutions with syslog-ng at their heart, I would like to say a few words about the others, some which were included in the previous edition of the blog.

LogAnalyzer from the makers of Rsyslog was a simple, easy to use PHP application a few years ago. While it has developed quite a lot, recently I could not get it to work with syslog-ng. Some of the popular monitoring software have syslog support to some extent, for example, Nagios, Cacti and several others. I have tested some of these, I have even sent patches and bug reports to enhance their syslog-ng support, but syslog is clearly not their focus, just one of the possible inputs.

The ELK stack (Elasticsearch + Logstash + Kibana) and Graylog2 have become popular recently, but they have their own log collectors instead of syslog-ng, and syslog is just one of many log sources. Syslog support is quite limited both in performance and protocol support. They recommend using file readers for collecting syslog messages, but that increases complexity, as it is an additional software on top of syslog(-ng), and filtering still needs to be done on the syslog side. Note that syslog-ng can send logs to Elasticsearch natively, which can greatly simplify your logging architecture.

Collecting and displaying metrics data

You can collect metrics data using syslog-ng. Examples include netdata or collectd. You can send the collected data to Graphite or Elasticsearch. Graphite has its own web interface, while you can use Kibana to query and visualize data collected to Elasticsearch.

Another option is to use Grafana. Originally, it was developed as an alternative web interface to the Graphite databases, but now it can also visualize data from many more data sources, including Elasticsearch. It can combine multiple data sources to a single dashboard and provides fine-grained access control.

Loki by Grafana is one of the latest applications that lets you aggregate and query log messages, and of course, to visualize logs using Grafana. It does not index the contents of log messages, only the labels associated with logs. This way, processing and storing log messages requires less resources, making Loki more cost-effective. Promtail, the log collector component of Loki, can collect log messages using the new, RFC 5424 syslog protocol. Learn here how syslog-ng can send its log messages to Loki.


One of the most popular web-based interfaces for log messages is Splunk. A returning question is whether to use syslog-ng or Splunk. Well, the issue is a bit of apples vs. oranges: they do not replace, but rather complement each other. As I already mentioned in the introduction, syslog-ng is good at reliably collecting and processing huge amounts of data. Splunk, on the other hand, is good at analyzing log messages for various purposes. Learn more about how you can integrate syslog-ng with Splunk from our white paper!

Syslog-ng based solutions

Here I show a number of syslog-ng based solutions. While every software described below is originally based on syslog-ng Open Source Edition (except for One Identity’s own syslog-ng Store Box (SSB)), there are already some large-scale deployments available also with syslog-ng Premium Edition as their syslog server.

  • The syslog-ng application and SSB focus on generic log management tasks and compliance.

  • LogZilla focuses on logs from Cisco devices.

  • Security Onion focuses on network and host security.

  • Recent syslog-ng releases are also able to store log messages directly into Elasticsearch, a distributed, scalable database system popular in DevOps environments, which enables the use of Kibana for analyzing log messages.

Benefits of using syslog-ng PE with these solutions include the logstore, a tamper-proof log storage (even if it means that your logs are stored twice), Windows support, and enterprise grade support.


LogZilla is the commercial reincarnation of one of the oldest syslog-ng web GUIs: PHP-Syslog-NG. It provides the familiar user interface of its predecessor, but also includes many new features. The user interface supports Cisco Mnemonics, extended graphing capabilities, and e-mail alerts. Behind the scenes, LDAP integration, message de-duplication, and indexing for quick searching were added for large datasets.

Over the past years, it received many small improvements. It became faster, and role-based access control was added, as well as the live tailing of log messages. Of course, all these new features come with a price; the free edition, which I have often recommended for small sites with Cisco logs is completely gone now.

A few years ago, a complete rewrite became available with many performance improvements under the hood and a new dashboard on the surface. Development never stopped, and now LogZilla can parse and enrich log messages, and can also automatically respond to events.

Therefore, it is an ideal solution for a network operations center (NOC) full of Cisco devices.

Web site: http://logzilla.net/

Security Onion

One of the most interesting projects utilizing syslog-ng is Security Onion, a free and open source Linux distribution for threat hunting, enterprise security monitoring, and log management. It is utilizing syslog-ng for log collection and log transfer, and uses the Elastic stack to store and search log messages. Even if you do not use its advanced security features, you can still use it for centralized log collection and as a nice web interface for your logs. But it is also worth getting acquainted with its security monitoring features, as it can provide you some useful insights about your network. Best of all, Security Onion is completely free and open source, with commercial support available for it.

You can learn more about it at https://www.syslog-ng.com/community/b/blog/posts/syslog-ng-and-security-onion

Elastisearch and Kibana

Elasticsearch is gaining momentum as the ultimate destination for log messages. There are two major reasons for this:

  • You can store arbitrary name-value pairs coming from structured logging or message parsing.

  • You can use Kibana as a search and visualization interface.

The syslog-ng application can send logs directly into Elasticsearch. We call this an ESK stack (Elasticsearch + syslog-ng + Kibana).

Learn how you can simplify your logging to Elasticsearch by using syslog-ng: https://www.syslog-ng.com/community/b/blog/posts/logging-to-elasticsearch-made-simple-with-syslog-ng

syslog-ng Store Box (SSB)

SSB is a log management appliance built on syslog-ng Premium Edition. SSB adds a powerful indexing engine, authentication and access control, customized reporting capabilities, and an easy-to-use web-based user interface.

Recent versions introduced AWS and Azure cloud support and horizontal scalability using remote logspaces. The new content-based alerting can send an e-mail alert whenever a match between the contents of a log message and a search expression is found.

SSB is really fast when it comes to indexing and searching log data. To put this scalability in context, the largest SSB appliance stores up to 10 terabytes of uncompressed, raw logs. With SSB’s current indexing performance of 100,000 events per second, that equates to approximately 8.6 billion logs per day or 1.7 terabytes of log data per day (calculating with an average event size of 200 bytes). Using compression, a single, large SSB appliance could store approximately one month of log data for an enterprise generating 1.7 terabytes of event data a day. This compares favorably to other solutions that require several nodes for collecting this amount of messages, and even more additional nodes for storing them. While storing logs to the cloud is getting popular, on-premise log storage is still a lot cheaper for a large amount of logs.

The GUI makes searching logs, configuring and managing the SSB easy. The search interface allows you to use wildcards and Boolean operators to perform complex searches, and drill down on the results. You can gain a quick overview and pinpoint problems fast by generating ad-hoc charts from the distribution of the log messages.

Configuring the SSB is done through the user interface. Most of the flexible filtering, classification and routing features in the syslog-ng Open Source and Premium Editions can be configured with the UI. Access and authentication policies can be set to integrate with Microsoft Active Directory, LDAP and RADIUS servers. The web interface is accessible through a network interface dedicated to the management traffic. This management interface is also used for backups, sending alerts, and other administrative traffic.

SSB is a ready-to-use appliance, which means that no software installation is necessary. It is easily scalable, because SSB is available both as a virtual machine and as a physical appliance, ranging from entry-level servers to multiple-unit behemoths. For mission critical applications, you can use SSB in High Availability mode. Enterprise-level support for SSB and syslog-ng PE is also available.

Read more about One Identity’s syslog-ng and SSB products here.

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