phpman > man > snmp_config(5)

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 configuration files in the following 4 directories, in or‐
       der: /etc/snmp, /usr/share/snmp, /usr/lib/x86_64-linux-gnu/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/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/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  ap‐
       plications  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,  in‐
       stead,  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
       special  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 appli‐
       cation  (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 applications (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  com‐
       ment and are not parsed.

INCLUDING OTHER CONFIGURATION FILES
       It  is  possible to include other configuration files for processing during normal configura‐
       tion file processing.:

              # include site specific config
              includeFile site.conf

       This will load the specified configuration file. The
       path to file must be either absolute, starting with '/',
       or relative. The relative path is then relative to the directory
       where the parent file with 'includeFile' directive resides.

       The included file name does not need to have '.conf' suffix.

              # include a all *.conf files in a directory
              includeDir /etc/snmp/config.d

       This will search specified directory for all files with '.conf'
       suffix and process them as if they were included using includeFile
       directive. The configuration files are not processed in any particular
       order.

       The specified directory must be absolute directory path.

API INTERFACE
       Information about writing C code that makes use of this system in either the agent's MIB mod‐
       ules 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)



V5.9.1                                       08 Mar 2010                              SNMP_CONFIG(5)