SNMP_CONFIG(5)							     Net-SNMP							    SNMP_CONFIG(5)

NAME

       snmp_config - handling of Net-SNMP configuration files

DESCRIPTION

       The  Net-SNMP package uses various configuration files to configure its applications.  This manual page merely describes the overall nature
       of them, so that the other manual pages don't have to.

DIRECTORIES SEARCHED

       First off, there are numerous places that configuration files can be found and read from.  By default, the applications look for configura-
       tion  files  in	the  following	4 directories, in order: /etc/snmp, /usr/share/snmp, /usr/lib(64)/snmp, and $HOME/.snmp.  In each of these
       directories, it looks for  files  snmp.conf,  snmpd.conf  and/or  snmptrapd.conf,  as  well  as	snmp.local.conf,  snmpd.local.conf  and/or
       snmptrapd.local.conf.  *.local.conf are always read last. In this manner, there are 8 default places a configuration file can exist for any
       given configuration file type.

       Additionally, the above default search path can be overridden by setting the environment variable SNMPCONFPATH to a colon-separated list of
       directories to search for.  The path for the persistent data should be included when running applications that use persistent storage, such
       as snmpd.

       Applications will read persistent configuration files in the following order of preference:

	      file in SNMP_PERSISTENT_FILE environment variable
	      directories in SNMPCONFPATH environment variable
	      directory defined by persistentDir snmp.conf variable
	      directory in SNMP_PERSISTENT_DIR environment variable
	      default /var/lib/net-snmp directory

       Finally, applications will write persistent configuration files in the following order of preference:

	      file in SNMP_PERSISTENT_FILE environment variable
	      directory defined by persistentDir snmp.conf variable
	      directory in SNMP_PERSISTENT_DIR environment variable
	      default /var/lib/net-snmp directory

       Note:  When using SNMP_PERSISTENT_FILE, the filename should match the application name.	For example, /var/net-snmp/snmpd.conf.

CONFIGURATION FILE TYPES

       Each application may use multiple configuration files, which will configure various different aspects of the  application.   For  instance,
       the  SNMP  agent  (snmpd)  knows  how to understand configuration directives in both the snmpd.conf and the snmp.conf files.  In fact, most
       applications understand how to read the contents of the snmp.conf files.  Note, however, that configuration directives  understood  in  one
       file  may  not  be understood in another file.  For further information, read the associated manual page with each configuration file type.
       Also, most of the applications support a -H switch on the command line that will list the configuration files it  will  look  for  and  the
       directives in each one that it understands.

       The snmp.conf configuration file is intended to be a application suite wide configuration file that supports directives that are useful for
       controlling the fundamental nature of all of the SNMP applications, such as how they all manipulate and parse the textual SNMP MIB files.

SWITCHING CONFIGURATION TYPES IN MID-FILE
       It's possible to switch in mid-file the configuration type that the parser is supposed to be reading.  Since  that  sentence  doesn't  make
       much sense, lets give you an example: say that you wanted to turn on packet dumping output for the agent by default, but you didn't want to
       do that for the rest of the applications (ie, snmpget, snmpwalk, ...).  Normally to enable packet dumping in the configuration  file  you'd
       need to put a line like:

	      dumpPacket true

       into the snmp.conf file.  But, this would turn it on for all of the applications.  So, instead, you can put the same line in the snmpd.conf
       file so that it only applies to the snmpd daemon.  However, you need to tell the parser to expect this line.  You do this by putting a spe-
       cial  type specification token inside a [] set.	In other words, inside your snmpd.conf file you could put the above snmp.conf directive by
       adding a line like so:

	      [snmp] dumpPacket true

       This tells the parser to parse the above line as if it were inside a snmp.conf file instead of an snmpd.conf file.  If you want to parse  a
       bunch  of  lines  rather  than  just  one then you can make the context switch apply to the remainder of the file or until the next context
       switch directive by putting the special token on a line by itself:

	      # make this file handle snmp.conf tokens:
	      [snmp]
	      dumpPacket true
	      logTimestamp true
	      # return to our original snmpd.conf tokens:
	      [snmpd]
	      rocommunity mypublic

       The same approach can be used to set configuration directives for a particular client application (or group of applications).  For example,
       any  program  that uses the 'snmp_parse_args()' call to handle command-line arguments (including the standard command-line tools shipped as
       part of the Net-SNMP distributions) will automatically read the config file 'snmpapp.conf'.  To set library-level settings for these appli-
       cations (but not other more-specific tools), use configuration such as the following:

	      [snmp] defCommunity myCommunity

       for a single directive, or

	      # make this file handle snmp.conf tokens:
	      [snmp]
	      defCommunity myCommunity
	      defVersion   2c
	      # return to our original snmpapp.conf tokens:
	      [snmpapp]

       for multiple settings.  Similarly for any other application token (as passed to init_snmp()).

COMMENTS

       Any lines beginning with the character '#' in the configuration files are treated as a comment and are not parsed.

INCLUDING OTHER CONFIGURATION FILES

       It is possible to include other configuration files for processing during normal configuration file processing.:

	      # include site specific config
	      include site.conf

       This will search every directory in the configuration path for files
       named site.conf, and will process those files before returning to the
       processing of the original file. Note that if '.conf' is omitted,
       it will be appended. That is, all configuration files must end
       in '.conf'.

API INTERFACE

       Information  about  writing  C  code that makes use of this system in either the agent's MIB modules or in applications can be found in the
       netsnmp_config_api(3) manual page.

SEE ALSO

       snmpconf(1), netsnmp_config_api(3), snmp.conf(5), snmpd.conf(5)

V5.7.2								    08 Mar 2010 						    SNMP_CONFIG(5)