snmp_config(5)

1SNMP_CONFIG(5)                     Net-SNMP                     SNMP_CONFIG(5)
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NAME

6       snmp_config - handling of Net-SNMP configuration files
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DESCRIPTION

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

14       First  off,  there  are numerous places that configuration files can be
15       found and read from.  By default, the applications look for  configura‐
16       tion  files  in  the  following  4  directories,  in  order: /etc/snmp,
17       /usr/share/snmp, /usr/lib(64)/snmp, and $HOME/.snmp.  In each of  these
18       directories,  it  looks  for  files with the extension of both conf and
19       local.conf (reading the second ones last).  In this manner, there are 8
20       default  places a configuration file can exist for any given configura‐
21       tion file type.
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23       Additionally, the above default search path can be overridden  by  set‐
24       ting the environment variable SNMPCONFPATH to a colon-separated list of
25       directories to search for.  The path for the persistent data should  be
26       included when running applications that use persistent storage, such as
27       snmpd.
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29       Applications will read persistent configuration files in the  following
30       order of preference:
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32              file in SNMP_PERSISTENT_FILE environment variable
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34              directories in SNMPCONFPATH environment variable
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36              directory defined by persistentDir snmp.conf variable
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38              directory in SNMP_PERSISTENT_DIR environment variable
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40              default /var/lib/net-snmp directory
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42       Finally,  applications will write persistent configuration files in the
43       following order of preference:
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45              file in SNMP_PERSISTENT_FILE environment variable
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47              directory defined by persistentDir snmp.conf variable
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49              directory in SNMP_PERSISTENT_DIR environment variable
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51              default /var/lib/net-snmp directory
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53       Note:  When using SNMP_PERSISTENT_FILE, the filename should  match  the
54       application name.  For example, /var/net-snmp/snmpd.conf.
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CONFIGURATION FILE TYPES

57       Each  application may use multiple configuration files, which will con‐
58       figure various different aspects of the application.  For instance, the
59       SNMP  agent (snmpd) knows how to understand configuration directives in
60       both the snmpd.conf and the snmp.conf files.  In  fact,  most  applica‐
61       tions  understand  how  to  read  the  contents of the snmp.conf files.
62       Note, however, that configuration directives understood in one file may
63       not  be  understood in another file.  For further information, read the
64       associated manual page with each configuration file type.   Also,  most
65       of  the  applications support a -H switch on the command line that will
66       list the configuration files it will look for  and  the  directives  in
67       each one that it understands.
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69       The  snmp.conf configuration file is intended to be a application suite
70       wide configuration file that supports directives that  are  useful  for
71       controlling  the  fundamental  nature  of all of the SNMP applications,
72       such as how they all manipulate and parse the textual SNMP MIB files.
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SWITCHING CONFIGURATION TYPES IN MID-FILE

75       It's possible to switch in mid-file the  configuration  type  that  the
76       parser  is  supposed  to  be reading.  Since that sentence doesn't make
77       much sense, lets give you an example: say that you wanted  to  turn  on
78       packet  dumping output for the agent by default, but you didn't want to
79       do that for the rest of the applications (ie, snmpget, snmpwalk,  ...).
80       Normally  to enable packet dumping in the configuration file you'd need
81       to put a line like:
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83              dumpPacket true
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85       into the snmp.conf file.  But, this would turn it on  for  all  of  the
86       applications.  So, instead, you can put the same line in the snmpd.conf
87       file so that it only applies to the snmpd daemon.  However, you need to
88       tell  the parser to expect this line.  You do this by putting a special
89       type specification token inside a [] set.  In other words, inside  your
90       snmpd.conf file you could put the above snmp.conf directive by adding a
91       line like so:
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93              [snmp] dumpPacket true
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95       This tells the parser to parse the above line as if it  were  inside  a
96       snmp.conf  file  instead of an snmpd.conf file.  If you want to parse a
97       bunch of lines rather than just one  then  you  can  make  the  context
98       switch  apply  to  the  remainder of the file or until the next context
99       switch directive by putting the special token on a line by itself:
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101              # make this file handle snmp.conf tokens:
102              [snmp]
103              dumpPacket true
104              logTimestamp true
105              # return to our original snmpd.conf tokens:
106              [snmpd]
107              rocommunity mypublic
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COMMENTS

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

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