Tools Index

1. Syslog-ng

Syslog-ng offers more than sysklogd, for example, we can log messages to different files based on pattern. It is possible to have both syslog-ng and sysklog, I will only configure syslog-ng and remove sysklog.

A simple way to "watch" log files is to use tail, with exception of faillog, see man faillog for more information.

        $ cd /var/log
        $ sudo tail -f messages kernel cron auth

1.1. Install syslog-ng

        $ prt-get depinst syslog-ng

1.4. Syslog-ng configuration

Example of /etc/syslog-ng.conf that configures syslog-ng matching tools already installed in the system and some that are part of tools.

Change /etc/rc.conf, replace sysklog with syslog-ng;

        #
        # /etc/rc.conf: system configuration
        #

        FONT=default
        KEYMAP=dvorak
        TIMEZONE="Europe/Lisbon"
        HOSTNAME=box
        SYSLOG=syslog-ng
        SERVICES=(lo net crond)

        # End of file

        $ sudo sh /etc/rc.d/syslog-ng start
        $ sudo sh /etc/rc.d/sysklogd stop

Description off global options used;

chain-hostnames(): Accepted values: yes | no; Default: no; Description: Enable or disable the chained hostname format. If the log message is forwarded to the log server via a relay, and the chain-hostnames() option is enabled, the relay adds its own hostname to the hostname of the client, separated with a / character.
create-dirs(): Accepted values: yes | no; Default: no; Description: Enable or disable directory creation for destination files.
use-dns(): Type: yes, no, persist_only; Default: yes; Description: Enable or disable DNS usage. The persist_only option attempts to resolve hostnames locally from file (for example from /etc/hosts). The syslog-ng OSE application blocks on DNS queries, so enabling DNS may lead to a Denial of Service attack.
stats_freq(): Accepted values: number; Default: 600; Description: The period between two STATS messages in seconds. STATS are log messages sent by syslog-ng, containing statistics about dropped log messages. Set to 0 to disable the STATS messages.
perm(): Accepted values: permission value; Default: 0600; Description: The default permission for output files. By default, syslog-ng changes the privileges of accessed files (for example /dev/null) to root.root 0600. To disable modifying privileges, use this option with the -1 value.
log-fifo-size(): Accepted values: number; Default: 10000; Description: The number of messages that the output queue can store.
log-msg-size(): Accepted values: number; Default: 8192; Description: Maximum length of a message in bytes. This length includes the entire message (the data structure and individual fields). The maximal value that can be set is 268435456 bytes (256MB). For messages using the IETF-syslog message format (RFC5424), the maximal size of the value of an SDATA field is 64kB.
flush-lines(): Type: number; Default: Use global setting.; Description: Specifies how many lines are flushed to a destination at a time. The syslog-ng OSE application waits for this number of lines to accumulate and sends them off in a single batch. Increasing this number increases throughput as more messages are sent in a single batch, but also increases message latency.

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