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RSYSLOG.CONF(5)                    Linux System Administration                    RSYSLOG.CONF(5)

       rsyslog.conf - rsyslogd(8) configuration file

       The rsyslog.conf file is the main configuration file for the rsyslogd(8) which logs system
       messages on *nix systems.  This file specifies rules for logging.   For  special  features
       see  the  rsyslogd(8)  manpage.  Rsyslog.conf  is backward-compatible with sysklogd's sys‐
       log.conf file. So if you migrate from sysklogd you can rename it and it should work.

       Note that this version of rsyslog ships with extensive documentation in html format.  This
       is  provided in the ./doc subdirectory and probably in a separate package if you installed
       rsyslog via a packaging system.  To use rsyslog's advanced features, you need to  look  at
       the html documentation, because the man pages only cover basic aspects of operation.

       Rsyslog  has a modular design. Consequently, there is a growing number of modules. See the
       html documentation for their full description.

       omsnmp SNMP trap output module

              Output module for GSS-enabled syslog

              Output module for MySQL

       omrelp Output module for the reliable RELP protocol (prevents message loss).  For details,
              see below at imrelp and the html documentation.  It can be used like this:

              *.*  :omrelp:server:port

              *.*  :omrelp: # actual sample

              Output module for PostgreSQL

              Generic database output module (Firebird/Interbase, MS SQL, Sybase, SQLite, Ingres,
              Oracle, mSQL)

       imfile Input module for text files

       imudp  Input plugin for UDP syslog. Replaces the deprecated -r option. Can  be  used  like

              $ModLoad imudp

              $UDPServerRun 514

       imtcp  Input  plugin  for plain TCP syslog. Replaces the deprecated -t option. Can be used
              like this:

              $ModLoad imtcp

              $InputTCPServerRun 514

       imrelp Input plugin for the RELP protocol. RELP can be used instead of UDP or plain
              TCP syslog to provide reliable delivery of syslog messages. Please note that
              plain TCP syslog does NOT provide truly reliable delivery, with it  messages
              may  be  lost  when  there is a connection problem or the server shuts down.
              RELP prevents message loss in those cases.  It can be used like this:

              $ModLoad imrelp

              $InputRELPServerRun 2514

              Input plugin for plain TCP and GSS-enable syslog

       immark Support for mark messages

       imklog Kernel logging. To include kernel log messages, you need to do

              $ModLoad imklog

              Please note that the klogd daemon is no longer necessary and consequently no
              longer provided by the rsyslog package.

              Unix sockets, including the system log socket. You need to specify

              $ModLoad imuxsock

              in  order  to  receive log messages from local system processes. This config
              directive should only left out if you know exactly what you are doing.

       Lines starting with a hash mark ('#') and empty lines  are  ignored.   Rsyslog.conf
       should contain following sections (sorted by recommended order in file):

       Global directives
              Global  directives  set  some global properties of whole rsyslog daemon, for
              example size of main message queue ($MainMessageQueueSize), loading external
              modules ($ModLoad) and so on.  All global directives need to be specified on
              a line by their own and must start with a dollar-sign. The complete list  of
              global  directives  can  be  found in html documentation in doc directory or
              online on web pages.

              Templates allow you to specify format of the logged message. They  are  also
              used  for  dynamic file name generation. They have to be defined before they
              are used in rules. For more info about templates see  TEMPLATES  section  of
              this manpage.

       Output channels
              Output  channels  provide  an  umbrella for any type of output that the user
              might want.  They have to be defined before they are used in rules. For more
              info about output channels see OUTPUT CHANNELS section of this manpage.

       Rules (selector + action)
              Every  rule  line  consists  of  two  fields, a selector field and an action
              field. These two fields are separated by one or more  spaces  or  tabs.  The
              selector field specifies a pattern of facilities and priorities belonging to
              the specified action.

       The selector field itself again consists of two parts, a facility and  a  priority,
       separated by a period ('.'). Both parts are case insensitive and can also be speci‐
       fied as decimal numbers, but don't do that, you have been warned.  Both  facilities
       and  priorities are described in syslog(3). The names mentioned below correspond to
       the similar LOG_-values in /usr/include/syslog.h.

       The facility is one of the following keywords: auth, authpriv, cron, daemon,  kern,
       lpr,  mail,  mark,  news,  security  (same  as auth), syslog, user, uucp and local0
       through local7. The keyword security should not be used anymore and  mark  is  only
       for internal use and therefore should not be used in applications.  Anyway, you may
       want to specify and redirect these messages here. The facility specifies  the  sub‐
       system that produced the message, i.e. all mail programs log with the mail facility
       (LOG_MAIL) if they log using syslog.

       The priority is one of the following keywords, in  ascending  order:  debug,  info,
       notice,  warning,  warn  (same  as warning), err, error (same as err), crit, alert,
       emerg, panic (same as emerg). The keywords error, warn and panic are deprecated and
       should not be used anymore. The priority defines the severity of the message.

       The behavior of the original BSD syslogd is that all messages of the specified pri‐
       ority and higher are logged according to the given  action.  Rsyslogd  behaves  the
       same, but has some extensions.

       In  addition to the above mentioned names the rsyslogd(8) understands the following
       extensions: An asterisk ('*') stands for all facilities or all priorities,  depend‐
       ing  on  where it is used (before or after the period). The keyword none stands for
       no priority of the given facility.

       You can specify multiple facilities with the same priority pattern in one statement
       using  the  comma  (',')  operator. You may specify as much facilities as you want.
       Remember that only the facility part from such a statement  is  taken,  a  priority
       part would be skipped.

       Multiple  selectors  may be specified for a single action using the semicolon (';')
       separator. Remember that each selector in the selector field is  capable  to  over‐
       write  the preceding ones. Using this behavior you can exclude some priorities from
       the pattern.

       Rsyslogd has a syntax extension to the original BSD source, that makes its use more
       intuitively.  You  may  precede every priority with an equals sign ('=') to specify
       only this single priority and not any of the above. You may also  (both  is  valid,
       too) precede the priority with an exclamation mark ('!') to ignore all that priori‐
       ties, either exact this one or this and any higher priority. If you use both exten‐
       sions  than  the  exclamation  mark  must occur before the equals sign, just use it

       The action field of a rule describes what to do with the message. In general,  mes‐
       sage  content  is  written  to a kind of "logfile". But also other actions might be
       done, like writing to a database table or forwarding to another host.

   Regular file
       Typically messages are logged to real files. The file has to be specified with full
       pathname, beginning with a slash ('/').

              *.*       /var/log/traditionalfile.log;RSYSLOG_TraditionalFileFormat       #
              log to a file in the traditional format

       Note: if you would like to use high-precision timestamps in your  log  files,  just
       remove  the  ";RSYSLOG_TraditionalFormat".  That  will select the default template,
       which, if not changed, uses RFC 3339 timestamps.

              *.*     /var/log/file.log # log to a file with RFC3339 timestamps

   Named pipes
       This version of rsyslogd(8) has support for logging output to named pipes  (fifos).
       A  fifo or named pipe can be used as a destination for log messages by prepending a
       pipe symbol ('|') to the name of the file. This is handy for debugging.  Note  that
       the fifo must be created with the mkfifo(1) command before rsyslogd(8) is started.

   Terminal and console
       If  the  file  you  specified  is  a  tty,  special tty-handling is done, same with

   Remote machine
       There are three ways to forward message: the traditional UDP  transport,  which  is
       extremely  lossy  but  standard, the plain TCP based transport which loses messages
       only during certain situations but is widely available and the RELP transport which
       does  not  lose messages but is currently available only as part of rsyslogd 3.15.0
       and above.

       To forward messages to another host via UDP, prepend the hostname with the at  sign
       ("@").   To  forward  it via plain tcp, prepend two at signs ("@@"). To forward via
       RELP, prepend the string ":omrelp:" in front of the hostname.

              *.* @

       In the example above, messages are forwarded via UDP to  the  machine,
       the  destination  port defaults to 514. Due to the nature of UDP, you will probably
       lose some messages in transit.  If you expect high traffic volume, you  can  expect
       to  lose  a  quite  noticeable number of messages (the higher the traffic, the more
       likely and severe is message loss).

       If you would like to prevent message loss, use RELP:
              *.* :omrelp:

       Note that a port number was given as there is no standard port for relp.

       Keep in mind that you need to load the correct input and output plugins (see  "Mod‐
       ules" above).

       Please  note  that rsyslogd offers a variety of options in regarding to remote for‐
       warding. For full details, please see the html documentation.

   List of users
       Usually critical messages are also directed to ``root'' on that  machine.  You  can
       specify  a  list of users that shall get the message by simply writing ":omusrmsg:"
       followed by the login name. You may specify more than one user by  separating  them
       with  commas (','). If they're logged in they get the message (for example: ":omus‐

   Everyone logged on
       Emergency messages often go to all users currently online to notify them that some‐
       thing  strange is happening with the system. To specify this wall(1)-feature use an

   Database table
       This allows logging of the message to a database table.  By default, a MonitorWare-
       compatible schema is required for this to work. You can create that schema with the
       createDB.SQL file that came with the rsyslog package. You can also  use  any  other
       schema  of  your liking - you just need to define a proper template and assign this
       template to the action.

       See the html documentation for further details on database logging.

       If the discard action is carried out, the  received  message  is  immediately  dis‐
       carded.  Discard  can  be  highly effective if you want to filter out some annoying
       messages that otherwise would fill your log files. To do that,  place  the  discard
       actions  early  in  your log files.  This often plays well with property-based fil‐
       ters, giving you great freedom in specifying what you do not want.

       Discard is just the single tilde character with no further parameters.

              *.*   ~      # discards everything.

   Output channel
       Binds an output channel definition (see there for details) to this  action.  Output
       channel  actions must start with a $-sign, e.g. if you would like to bind your out‐
       put channel definition "mychannel" to the action, use "$mychannel". Output channels
       support template definitions like all all other actions.

   Shell execute
       This executes a program in a subshell. The program is passed the template-generated
       message as the only command line parameter. Rsyslog waits until the program  termi‐
       nates and only then continues to run.


       The program-to-execute can be any valid executable. It receives the template string
       as a single parameter (argv[1]).

       Rsyslog offers three different types "filter conditions":
          * "traditional" severity and facility based selectors
          * property-based filters
          * expression-based filters

       Selectors are the traditional way of filtering syslog  messages.   They  have  been
       kept in rsyslog with their original syntax, because it is well-known, highly effec‐
       tive and also needed for compatibility with stock syslogd configuration  files.  If
       you  just  need  to  filter based on priority and facility, you should do this with
       selector lines. They are not second-class citizens in rsyslog and  offer  the  best
       performance for this job.

   Property-Based Filters
       Property-based  filters  are  unique to rsyslogd. They allow to filter on any prop‐
       erty, like HOSTNAME, syslogtag and msg.

       A property-based filter must start with a colon in column 0.  This  tells  rsyslogd
       that  it is the new filter type. The colon must be followed by the property name, a
       comma, the name of the compare operation to carry out, another comma and  then  the
       value  to compare against. This value must be quoted.  There can be spaces and tabs
       between the commas. Property names and compare operations  are  case-sensitive,  so
       "msg"  works,  while  "MSG" is an invalid property name. In brief, the syntax is as

              :property, [!]compare-operation, "value"

       The following compare-operations are currently supported:

                     Checks if the string provided in value is contained in the property

                     Compares the "value" string provided and the property contents. These
                     two values must be exactly equal to match.

                     Checks if the value is found exactly at the beginning of the property

                     Compares the property against the provided regular expression.

   Expression-Based Filters
       See the html documentation for this feature.

       Every output in rsyslog uses templates - this holds true for files,  user  messages
       and  so  on. Templates compatible with the stock syslogd formats are hardcoded into
       rsyslogd. If no template is specified, we use one  of  these  hardcoded  templates.
       Search for "template_" in syslogd.c and you will find the hardcoded ones.

       A  template  consists of a template directive, a name, the actual template text and
       optional options. A sample is:

              $template MyTemplateName,"\7Text %property% some more text\n",<options>

       The "$template" is the template directive. It tells rsyslog that this line contains
       a  template.  The  backslash is an escape character. For example, \7 rings the bell
       (this is an ASCII value), \n is a new line. The set in rsyslog is a bit  restricted

       All text in the template is used literally, except for things within percent signs.
       These are properties and allow you access to the contents of  the  syslog  message.
       Properties  are  accessed  via  the property replacer and it can for example pick a
       substring or do date-specific formatting. More on this  is  the  PROPERTY  REPLACER
       section of this manpage.

       To escape:
          % = \%
          \ = \\ --> '\' is used to escape (as in C)
       $template TraditionalFormat,"%timegenerated% %HOSTNAME% %syslogtag%%msg%\n"

       Properties can be accessed by the property replacer (see there for details).

       Please note that templates can also by used to generate selector lines with dynamic
       file names.  For example, if you would like to split syslog messages from different
       hosts to different files (one per host), you can define the following template:

              $template DynFile,"/var/log/system-%HOSTNAME%.log"

       This  template  can  then  be  used  when defining an output selector line. It will
       result in something like "/var/log/system-localhost.log"

   Template options
       The <options> part is optional. It carries  options  influencing  the  template  as
       whole.   See  details  below. Be sure NOT to mistake template options with property
       options - the later ones are processed by the property replacer and apply to a SIN‐
       GLE property, only (and not the whole template).

       Template options are case-insensitive. Currently defined are:

              sql    format  the string suitable for a SQL statement in MySQL format. This
                     will replace single quotes ("'") and the backslash character by their
                     backslash-escaped counterpart ("´" and "\") inside each field. Please
                     note that in MySQL configuration, the NO_BACKSLASH_ESCAPES mode  must
                     be turned off for this format to work (this is the default).

              stdsql format  the string suitable for a SQL statement that is to be sent to
                     a standards-compliant sql server. This  will  replace  single  quotes
                     ("'")  by  two  single quotes ("''") inside each field.  You must use
                     stdsql together with MySQL if in  MySQL  configuration  the  NO_BACK‐
                     SLASH_ESCAPES is turned on.

       Either the sql or stdsql option MUST be specified when a template is used for writ‐
       ing to a database, otherwise injection might occur. Please note  that  due  to  the
       unfortunate fact that several vendors have violated the sql standard and introduced
       their own escape methods, it is impossible to have a single option  doing  all  the
       work.   So  you  yourself  must  make  sure you are using the right format.  If you
       choose the wrong one, you are still vulnerable to sql injection.

       Please note that the database writer *checks* that the sql option is present in the
       template.  If it is not present, the write database action is disabled.  This is to
       guard you against accidental forgetting it and  then  becoming  vulnerable  to  SQL
       injection. The sql option can also be useful with files - especially if you want to
       import them into a database on another machine for performance reasons. However, do
       NOT use it if you do not have a real need for it - among others, it takes some toll
       on the processing time. Not much, but on a really busy system you might  notice  it

       The default template for the write to database action has the sql option set.

   Template examples
       Please  note  that the samples are split across multiple lines. A template MUST NOT
       actually be split across multiple lines.

       A template that resembles traditional syslogd file output:

              $template TraditionalFormat,"%timegenerated% %HOSTNAME%

       A template that tells you a little more about the message:

              $template  precise,"%syslogpriority%,%syslogfacility%,%timegenerated%,%HOST‐

       A template for RFC 3164 format:

              $template RFC3164fmt,"<%PRI%>%TIMESTAMP% %HOSTNAME% %syslogtag%%msg%"

       A template for the format traditionally used for user messages:

              $template usermsg," XXXX%syslogtag%%msg%\n\r"

       And a template with the traditional wall-message format:

              $template wallmsg,"\r\n\7Message from syslogd@%HOSTNAME% at %timegenerated%"

       A template that can be used for writing to a database (please note the SQL template

              $template MySQLInsert,"insert iut, message, receivedat values ('%iut%',
              '%msg:::UPPERCASE%', '%timegenerated:::date-mysql%') into systemevents\r\n",

              NOTE 1: This template is embedded into core application under name StdDBFmt
              , so you don't need to define it.

              NOTE 2: You have to have MySQL module installed to use this template.

       Output  Channels  are  a  new concept first introduced in rsyslog 0.9.0. As of this
       writing, it is most likely that they will be replaced by something different in the
       future.   So  if  you use them, be prepared to change you configuration file syntax
       when you upgrade to a later release.

       Output channels are defined via an $outchannel directive. It's syntax  is  as  fol‐

              $outchannel name,file-name,max-size,action-on-max-size

       name  is  the name of the output channel (not the file), file-name is the file name
       to be written to, max-size the maximum allowed size and action-on-max-size  a  com‐
       mand to be issued when the max size is reached. This command always has exactly one
       parameter. The binary is that part of action-on-max-size before  the  first  space,
       its parameter is everything behind that space.

       Keep in mind that $outchannel just defines a channel with "name". It does not acti‐
       vate it.  To do so, you must use a selector line (see below).  That  selector  line
       includes the channel name plus ":omfile:$" in front of it. A sample might be:

              *.* :omfile:$mychannel

       The  property  replacer  is  a core component in rsyslogd's output system. A syslog
       message has a number of well-defined properties (see below). Each of  this  proper‐
       ties  can be accessed and manipulated by the property replacer. With it, it is easy
       to use only part of a property value or manipulate the value,  e.g.  by  converting
       all characters to lower case.

   Accessing Properties
       Syslog  message  properties are used inside templates. They are accessed by putting
       them between percent signs. Properties can be modified by  the  property  replacer.
       The full syntax is as follows:


       propname is the name of the property to access.  It is case-sensitive.

   Available Properties
       msg    the MSG part of the message (aka "the message" ;))

       rawmsg the message exactly as it was received from the socket. Should be useful for

              hostname from the message

              hostname of the system the message was received from (in a relay chain, this
              is  the  system  immediately in front of us and not necessarily the original

              TAG from the message

              the "static" part of the tag, as defined by BSD syslogd. For  example,  when
              TAG is "named[12345]", programname is "named".

       PRI    PRI part of the message - undecoded (single value)

              the PRI part of the message in a textual form (e.g. "syslog.info")

       IUT    the  monitorware  InfoUnitType  - used when talking to a MonitorWare backend
              (also for phpLogCon)

              the facility from the message - in numerical form

              the facility from the message - in text form

              severity from the message - in numerical form

              severity from the message - in text form

              timestamp when the message was RECEIVED. Always in high resolution

              timestamp from the message. Resolution depends on what was provided  in  the
              message (in most cases, only seconds)

              alias for timereported

              The  contents  of the PROTOCOL-VERSION field from IETF draft draft-ietf-sys‐

              The contents of the STRUCTURED-DATA field from IETF draft draft-ietf-syslog-

              The  contents of the APP-NAME field from IETF draft draft-ietf-syslog-proto‐

       PROCID The contents of the PROCID field from IETF draft draft-ietf-syslog-protocol

       MSGID  The contents of the MSGID field from IETF draft draft-ietf-syslog-protocol

       $NOW   The current date stamp in the format YYYY-MM-DD

       $YEAR  The current year (4-digit)

       $MONTH The current month (2-digit)

       $DAY   The current day of the month (2-digit)

       $HOUR  The current hour in military (24 hour) time (2-digit)

              The current minute (2-digit)

       Properties starting with a $-sign are so-called system  properties.  These  do  NOT
       stem from the message but are rather internally-generated.

   Character Positions
       FromChar  and  toChar  are used to build substrings. They specify the offset within
       the string that should be copied. Offset counting starts at 1, so if  you  need  to
       obtain  the  first  2  characters  of  the  message  text, you can use this syntax:
       "%msg:1:2%". If you do not wish to specify from and to, but  you  want  to  specify
       options,  you  still  need to include the colons. For example, if you would like to
       convert the full message text to lower case, use "%msg:::lowercase%". If you  would
       like  to  extract from a position until the end of the string, you can place a dol‐
       lar-sign ("$") in toChar (e.g. %msg:10:$%, which will extract from position  10  to
       the end of the string).

       There  is  also  support for regular expressions.  To use them, you need to place a
       "R" into FromChar.  This tells rsyslog that a regular expression instead  of  posi‐
       tion-based  extraction  is desired. The actual regular expression must then be pro‐
       vided in toChar. The regular expression must be followed by the string "--end".  It
       denotes  the  end of the regular expression and will not become part of it.  If you
       are using regular expressions, the property replacer will return the  part  of  the
       property  text  that  matches  the  regular  expression.  An example for a property
       replacer sequence with a regular expression is: "%msg:R:.*Sev:. \(.*\) \[.*--end%"

       Also, extraction can be done based on so-called "fields". To do  so,  place  a  "F"
       into FromChar. A field in its current definition is anything that is delimited by a
       delimiter character. The delimiter by default is TAB (US-ASCII value  9).  However,
       if  can  be  changed  to any other US-ASCII character by specifying a comma and the
       decimal US-ASCII value of the delimiter immediately after the "F". For example,  to
       use  comma  (",") as a delimiter, use this field specifier: "F,44".  If your syslog
       data is delimited, this is a quicker way to extract than  via  regular  expressions
       (actually,  a  *much*  quicker  way).  Field  counting  starts  at 1. Field zero is
       accepted, but will always lead to a "field not found" error. The same happens if  a
       field  number  higher  than  the number of fields in the property is requested. The
       field number must be placed in the "ToChar" parameter. An  example  where  the  3rd
       field  (delimited  by  TAB)  from  the  msg  property  is  extracted is as follows:
       "%msg:F:3%". The same example with semicolon as delimiter is "%msg:F,59:3%".

       Please note that the special characters "F" and "R" are case-sensitive. Only  upper
       case  works,  lower  case will return an error. There are no white spaces permitted
       inside the sequence (that will lead to error messages  and  will  NOT  provide  the
       intended result).

   Property Options
       Property  options  are  case-insensitive.  Currently,  the  following  options  are

              convert property to lowercase only

              convert property text to uppercase only

              The last LF in the message (if any), is dropped. Especially useful for PIX.

              format as mysql date

              format as RFC 3164 date

              format as RFC 3339 date

              replace control characters (ASCII value 127 and values less then 32) with an
              escape  sequence.  The sequence is "#<charval>" where charval is the 3-digit
              decimal value of the control character. For example, a  tabulator  would  be
              replaced by "#009".

              replace control characters by spaces

              drop  control characters - the resulting string will neither contain control
              characters, escape sequences nor any other replacement character like space.

       Rsyslogd supports queued operations to handle offline  outputs  (like  remote  sys‐
       logd's  or database servers being down). When running in queued mode, rsyslogd buf‐
       fers messages to memory and optionally to disk (on an as-needed basis). Queues sur‐
       vive rsyslogd restarts.

       It  is  highly  suggested  to  use remote forwarding and database writing in queued
       mode, only.

       To learn more about queued operations, see the html documentation.

              Configuration file for rsyslogd

       rsyslogd(8), logger(1), syslog(3)

       The complete documentation can be found in the doc folder of the rsyslog  distribu‐
       tion or online at


       Please  note that the man page reflects only a subset of the configuration options.
       Be sure to read the html documentation for all features and details. This is  espe‐
       cially vital if you plan to set up a more-then-extremely-simple system.

       rsyslogd is taken from sysklogd sources, which have been heavily modified by Rainer
       Gerhards (rgerhards AT adiscon.com) and others.

Version 7.2.0                            22 October 2012                          RSYSLOG.CONF(5)

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