syslog-ng Premium Edition 6.0.21 - Administration Guide

Procedure 4.1. Configuring syslog-ng on client hosts

Purpose: 

To configure syslog-ng on a client host, complete the following steps.

Steps: 

1. Install the syslog-ng application on the host. For details installing syslog-ng on specific operating systems, see Chapter 3, Installing syslog-ng.

2. Configure the local sources to collect the log messages of the host. Starting with version 3.2, syslog-ng PE automatically collects the log messages that use the native system logging method of the platform, for example, messages from /dev/log on Linux, or /dev/klog on FreeBSD. For a complete list of messages that are collected automatically, see the section called “Collecting the system-specific log messages of a platform”.

   Add sources to collect the messages from your log files. File sources look like this:

   source s_myfilesource {
           file("/var/log/myapplication.log" follow-freq(1)); };

   Name every source uniquely. For details on configuring file sources, see the section called “Collecting messages from text files”.

   TIP: Many applications send log messages to logfiles by default (for example, the Roundcube webmail client, or the ProFTPD FTP server), but can be configured to send them to syslog instead. If possible, it is recommended to reconfigure the application that way.

   NOTE: The default configuration file of syslog-ng PE collects platform-specific log messages and the internal log messages of syslog-ng PE. source s_local { system(); internal(); };

3. Create a network destination that points directly to the syslog-ng server, or to a local relay. The network destination greatly depends on the protocol that your log server or relay accepts messages. Many systems still use the legacy BSD-syslog protocol (RFC3162) over the unreliable UDP transport:

   destination d_network { network("10.1.2.3" transport("udp")); };

   However, if possible, use the much more reliable IETF-syslog protocol over TCP transport:

   destination d_network { syslog("10.1.2.3" transport("tcp")); };

4. Create a log statement connecting the local sources to the syslog-ng server or relay. For example:

   log {
           source(s_local); destination(d_network); };

5. If the logs will also be stored locally on the host, create local file destinations.

   NOTE: The default configuration of syslog-ng PE places the collected messages into the /var/log/messages file: destination d_local { file("/var/log/messages"); };

6. Create a log statement connecting the local sources to the file destination.

   NOTE: The default configuration of syslog-ng PE has only one log statement: log { source(s_local); destination(d_local); };

7. Set filters, macros and other features and options (for example TLS encryption) as necessary.

   Example 4.1. The default configuration file of syslog-ng PE

   The following is a simple configuration file that collects local log messages to the /var/log/messages file.

   @version: 6.0
   @include "scl.conf"
   source s_local { system(); internal(); };
   destination d_local {
               file("/var/log/messages"); };
   log { source(s_local); destination(d_local); };

   
   

   Example 4.2. A simple configuration for clients

   The following configuration file collects local log messages and the log messages of syslog-ng PE, and forwards them to a log server using the IETF-syslog protocol.

   @version: 6.0
   @include "scl.conf"
   source s_local { system(); internal(); };
   destination d_syslog_tcp {
                syslog("192.168.1.1" transport("tcp") port(2010)); };
   log { source(s_local);destination(d_syslog_tcp); };

   
   

   If you experience difficulties, see Chapter 19, Troubleshooting syslog-ng for tips on solving common problems.

Procedure 4.2. Configuring syslog-ng on server hosts

Purpose: 

To configure syslog-ng on a server host, complete the following steps.

Steps: 

1. Install the syslog-ng application on the host. For details installing syslog-ng on specific operating systems, see Chapter 3, Installing syslog-ng.

2. Starting with version 3.2, syslog-ng PE automatically collects the log messages that use the native system logging method of the platform, for example, messages from /dev/log on Linux, or /dev/klog on FreeBSD. For a complete list of messages that are collected automatically, see the section called “Collecting the system-specific log messages of a platform”.

3. Configure the network sources that collect the log messages sent by the clients and relays. How the network sources should be configured depends also on the capabilities of your client hosts: many older networking devices support only the legacy BSD-syslog protocol (RFC3164) using UDP transport:

   source s_network { syslog(ip(10.1.2.3) transport("udp")); };

   However, if possible, use the much more reliable TCP transport:

   source s_network { syslog(ip(10.1.2.3) transport("tcp")); };

   For other options, see the section called “Collecting messages using the IETF syslog protocol (syslog() driver)” and the section called “Collecting messages from remote hosts using the BSD syslog protocol”.

   NOTE: Starting with syslog-ng PE version 3.2, the syslog() source driver can handle both BSD-syslog (RFC 3164) and IETF-syslog (RFC 5424-26) messages.

4. Create local destinations that will store the log messages, for example file- or program destinations. The default configuration of syslog-ng PE places the collected messages into the /var/log/messages file:

   destination d_local {
       file("/var/log/messages"); };

   If you want to create separate logfiles for every client host, use the ${HOST} macro when specifying the filename, for example:

   destination d_local {
       file("/var/log/messages_${HOST}"); };

   For details on further macros and how to use them, see Chapter 14, Manipulating messages.

5. Create a log statement connecting the sources to the local destinations.

   log {
           source(s_local); source(s_network); destination(d_local); };

6. Set filters, options (for example TLS encryption) and other advanced features as necessary.

   NOTE: By default, the syslog-ng server will treat the relayed messages as if they were created by the relay host, not the host that originally sent them to the relay. In order to use the original hostname on the syslog-ng server, use the keep-hostname(yes) option both on the syslog-ng relay and the syslog-ng server. This option can be set individually for every source if needed. If you are relaying log messages and want to resolve IP addresses to hostnames, configure the first relay to do the name resolution.

   Example 4.3. A simple configuration for servers

   The following is a simple configuration file for syslog-ng Premium Edition that collects incoming log messages and stores them in a text file.

   @version: 6.0
   @include "scl.conf"
       options {
           time-reap(30);
           mark-freq(10);
           keep-hostname(yes);
           };
       source s_local { system(); internal(); };
       source s_network {
           syslog(transport(tcp));
           };
       destination d_logs {
           file(
               "/var/log/syslog-ng/logs.txt"
               owner("root")
               group("root")
               perm(0777)
               ); };
       log { source(s_local); source(s_network); destination(d_logs); };

   
   

   If you experience difficulties, see Chapter 19, Troubleshooting syslog-ng for tips on solving common problems.