Ubuntu Manpage: snmp.conf - configuration files for the Net-SNMP applications

Provided by: libsnmp-base_5.9.3+dfsg-1ubuntu1_all

NAME

       snmp.conf - configuration files for the Net-SNMP applications

DESCRIPTION

       Applications  built  using  the Net-SNMP libraries typically use one or more configuration
       files to  control  various  aspects  of  their  operation.   These  files  (snmp.conf  and
       snmp.local.conf)  can  be  located  in  one  of  several  locations,  as  described in the
       snmp_config(5) manual page.

       In particular, /etc/snmp/snmp.conf is a common file, containing the settings shared by all
       users  of the system.  ~/.snmp/snmp.conf is a personal file, with the settings specific to
       a particular user.

HOST-SPECIFIC FILES

       Host-specific files may also be loaded and will be searched for if  a  transport  name  is
       specified  that  matches  a  PATH/hosts/HOST.conf  file.   For  example,  if  you wanted a
       particular host to use SNMPv2c by default you could create a ~/.snmp/hosts/NAME.conf  file
       and in it put:

              defVersion 2c

       Any  connections  set  to  connect  to  the  hostname NAME will use SNMPv2c.  Also see the
       transport token below for additional host-specific examples.

       Host-specific configuration files are loaded at the time the connection is  opened.   Thus
       they're  generally  loaded after all other configuration files and can be used to override
       settings from the generic files.

       To avoid loading any host-specific config files  set  "dontLoadHostConfig  true"  in  your
       snmp.conf file.

COMMAND-LINE OPTIONS

       All  of  the  tokens  described  in  this file can be used on the command line of Net-SNMP
       applications   as   well    by    prefixing    them    with    "--".     EG,    specifying
       --dontLoadHostConfig=true  on  the  command line will turn of loading of the host specific
       configuration files.

IMPORTANT NOTE

       Several of these directives may contain sensitive  information  (such  as  pass  phrases).
       Configuration  files  that  include  such  settings  should  only  be readable by the user
       concerned.

       As well as application-specific configuration tokens, there are  several  directives  that
       relate  to  standard  library  behaviour, relevant to most Net-SNMP applications.  Many of
       these correspond to standard command-line options, which are described in  the  snmpcmd(1)
       manual page.

       These directives can be divided into several distinct groups.

CLIENT BEHAVIOUR

defDomain application domain
The transport domain that should be used for a certain application type unless
something else is specified.

defTarget application domain target
The target that should be used for connections to a certain application if the
connection should be in a specific domain.

defaultPort PORT
defines the default UDP port that client SNMP applications will attempt to connect
to. This can be overridden by explicitly including a port number in the AGENT
specification. See the snmpcmd(1) manual page for more details.

If not specified, the default value for this token is 161.

transport HOSTSPECIFIER
This special token should go into a hostname-specific configuration file in a hosts
sub-directory. For example if the file hosts/foo.conf exists in the search path it
will be loaded if a transport name of foo was used. Within the foo.conf file you
may put both general snmp.conf settings as well as a special transport string to
specify the destination to connect to. For example, putting:

transport tcp:foo.example.com:9876

in the hosts/foo.conf file will make applications referencing the foo hostname
(e.g. snmpget) to actually connect via TCP to foo.exmaple.com on port 9876.

defVersion (1|2c|3)
defines the default version of SNMP to use. This can be overridden using the -v
option.

defCommunity STRING
defines the default community to use for SNMPv1 and SNMPv2c requests. This can be
overridden using the -c option.

alias NAME DEFINITION
Creates an aliased tied to NAME for a given transport definition. The alias can
the be referred to using an alias: prefix. Eg, a line of "alias here
udp:127.0.0.1:6161" would allow you to use a destination host of "alias:here"
instead of "udp:127.0.0.1:6161". This becomes more useful with complex transport
addresses involving IPv6 addresses, etc.

dumpPacket yes
defines whether to display a hexadecimal dump of the raw SNMP requests sent and
received by the application. This is equivalent to the -d option.

doDebugging (1|0)
turns on debugging for all applications run if set to 1.

debugTokens TOKEN[,TOKEN...]
defines the debugging tokens that should be turned on when doDebugging is set.
This is equivalent to the -D option.

16bitIDs yes
restricts requestIDs, etc to 16-bit values.

The SNMP specifications define these ID fields as 32-bit quantities, and the Net-
SNMP library typically initialises them to random values for security. However
certain (broken) agents cannot handle ID values greater than 2^16 - this option
allows interoperability with such agents.

clientaddr [<transport-specifier>:]<transport-address>
specifies the source address to be used by command-line applications when sending
SNMP requests. See snmpcmd(1) for more information about the format of addresses.

This value is also used by snmpd when generating notifications.

clientaddrUsesPort no
specifies, if clientaddr option contains a port number. Set this option to "yes",
if clientaddr contains a port number and this port should be used for sending
outgoing SNMP requests. This option only affects IPv4 client addresses and is
ignored for IPv6 client addresses.

clientRecvBuf INTEGER
specifies the desired size of the buffer to be used when receiving responses to
SNMP requests. If the OS hard limit is lower than the clientRecvBuf value, then
this will be used instead. Some platforms may decide to increase the size of the
buffer actually used for internal housekeeping.

This directive will be ignored if the platforms does not support setsockopt().

clientSendBuf INTEGER
is similar to clientRecvBuf, but applies to the size of the buffer used when
sending SNMP requests.

noRangeCheck yes
disables the validation of varbind values against the MIB definition for the
relevant OID. This is equivalent to the -Ir option.

This directive is primarily relevant to the snmpset command, but will also apply to
any application that calls snmp_add_var() with a non-NULL value.

noTokenWarnings
disables warnings about unknown config file tokens.

reverseEncodeBER (1|yes|true|0|no|false)
controls how the encoding of SNMP requests is handled.

The default behaviour is to encode packets starting from the end of the PDU and
working backwards. This directive can be used to disable this behaviour, and build
the encoded request in the (more obvious) forward direction.

It should not normally be necessary to change this setting, as the encoding is
basically the same in either case - but working backwards typically produces a
slightly more efficient encoding, and hence a smaller network datagram.

dontLoadHostConfig (1|yes|true|0|no|false)
Specifies whether or not the host-specific configuration files are loaded. Set to
"true" to turn off the loading of the host specific configuration files.

retries INTEGER
Specifies the number of retries to be used in the requests.

timeout INTEGER
Specifies the timeout in seconds between retries.

SNMPv1/SNMPv2c SETTINGS

       disableSNMPv1  (1|yes|true|0|no|false)

       disableSNMPv2c (1|yes|true|0|no|false)
              Disables protocol versions at  runtime.  Incoming  and  outgoing  packets  for  the
              protocol will be dropped.

SNMPv3 SETTINGS

disableSNMPv3 (1|yes|true|0|no|false)
Disables protocol versions at runtime. Incoming and outgoing packets for the
protocol will be dropped.

defSecurityName STRING
defines the default security name to use for SNMPv3 requests. This can be
overridden using the -u option.

defSecurityLevel noAuthNoPriv|authNoPriv|authPriv
defines the default security level to use for SNMPv3 requests. This can be
overridden using the -l option.

If not specified, the default value for this token is noAuthNoPriv.

Note: authPriv is only available if the software has been compiled to use the
OpenSSL libraries.

defPassphrase STRING

defAuthPassphrase STRING

defPrivPassphrase STRING
define the default authentication and privacy pass phrases to use for SNMPv3
requests. These can be overridden using the -A and -X options respectively.

The defPassphrase value will be used for the authentication and/or privacy pass
phrases if either of the other directives are not specified.

defAuthType MD5|SHA|SHA-512|SHA-384|SHA-256|SHA-224

defPrivType DES|AES
define the default authentication and privacy protocols to use for SNMPv3 requests.
These can be overridden using the -a and -x options respectively.

If not specified, SNMPv3 requests will default to MD5 authentication and DES
encryption.

Note: If the software has not been compiled to use the OpenSSL libraries, then
only MD5 authentication is supported. Neither SHA authentication nor any
form of encryption will be available.

defContext STRING
defines the default context to use for SNMPv3 requests. This can be overridden
using the -n option.

If not specified, the default value for this token is the default context (i.e. the
empty string "").

defSecurityModel STRING
defines the security model to use for SNMPv3 requests. The default value is "usm"
which is the only widely used security model for SNMPv3.

defAuthMasterKey 0xHEXSTRING

defPrivMasterKey 0xHEXSTRING

defAuthLocalizedKey 0xHEXSTRING

defPrivLocalizedKey 0xHEXSTRING
define the (hexadecimal) keys to be used for SNMPv3 secure communications. SNMPv3
keys are frequently derived from a passphrase, as discussed in the defPassphrase
section above. However for improved security a truely random key can be generated
and used instead (which would normally has better entropy than a password unless it
is amazingly long). The directives are equivalent to the short-form command line
options -3m, -3M, -3k, and -3K.

Localized keys are master keys which have been converted to a unique key which is
only suitable for on particular SNMP engine (agent). The length of the key needs
to be appropriate for the authentication or encryption type being used (auth keys:
MD5=16 bytes, SHA1=20 bytes; priv keys: DES=16 bytes (8 bytes of which is used as
an IV and not a key), and AES=16 bytes).

sshtosnmpsocket PATH
Sets the path of the sshtosnmp socket created by an application (e.g. snmpd)
listening for incoming ssh connections through the sshtosnmp unix socket.

sshtosnmpsocketperms MODE [OWNER [GROUP]]
Sets the mode, owner and group of the sshtosnmp socket created by an application
(e.g. snmpd) listening for incoming ssh connections through the sshtosnmp unix
socket. The socket needs to be read/write privileged for SSH users that are
allowed to connect to the SNMP service (VACM access still needs to be granted as
well, most likely through the TSM security model).

sshusername NAME
Sets the SSH user name for logging into the remote system.

sshpubkey FILE
Set the public key file to use when connecting to a remote system.

sshprivkey FILE
Set the private key file to use when connecting to a remote system.

SERVER BEHAVIOUR

persistentDir DIRECTORY
defines the directory where snmpd and snmptrapd store persistent configuration
settings.

If not specified, the persistent directory defaults to /var/lib/snmp

noPersistentLoad yes

noPersistentSave yes
disable the loading and saving of persistent configuration information.

Note: This will break SNMPv3 operations (and other behaviour that relies on
changes persisting across application restart). Use With Care.

tempFilePattern PATTERN
defines a filename template for creating temporary files, for handling input to and
output from external shell commands. Used by the mkstemp() and mktemp() functions.

If not specified, the default pattern is "/tmp/snmpdXXXXXX".

serverRecvBuf INTEGER
specifies the desired size of the buffer to be used when receiving incoming SNMP
requests. If the OS hard limit is lower than the serverRecvBuf value, then this
will be used instead. Some platforms may decide to increase the size of the buffer
actually used for internal housekeeping.

This directive will be ignored if the platforms does not support setsockopt().

serverSendBuf INTEGER
is similar to serverRecvBuf, but applies to the size of the buffer used when
sending SNMP responses.

sourceFilterType none|acceptlist|blocklist
specifies whether or not addresses added with sourceFilterAddress are accepted or
blocked. The default is none, indicating that incoming packets will not be checked
agains the filter list.

sourceFilterAddress ADDRESS
specifies an address to be added to the source address filter list.
sourceFilterType configuration determines whether or not addresses are accepted or
blocked.

MIB HANDLING

       mibdirs DIRLIST
              specifies a list of directories to search for MIB files.  This operates in the same
              way as the -M option - see snmpcmd(1) for details.  Note that  this  value  can  be
              overridden by the MIBDIRS environment variable, and the -M option.

       mibs MIBLIST
              specifies  a  list of MIB modules (not files) that should be loaded.  This operates
              in the same way as the -m option - see snmpcmd(1) for details.  Note that this list
              can be overridden by the MIBS environment variable, and the -m option.

       mibfile FILE
              specifies  a  (single) MIB file to load, in addition to the list read from the mibs
              token (or equivalent configuration).  Note that this value can be overridden by the
              MIBFILES environment variable.

       showMibErrors (1|yes|true|0|no|false)
              whether to display MIB parsing errors.

       commentToEOL (1|yes|true|0|no|false)
              whether  MIB  parsing should be strict about comment termination.  Many MIB writers
              assume that ASN.1 comments extend to the end of the text line,  rather  than  being
              terminated by the next "--" token.  This token can be used to accept such (strictly
              incorrect) MIBs.
              Note that this directive was previous (mis-)named strictCommentTerm, but  with  the
              reverse  behaviour  from  that  implied  by  the name.  This earlier token is still
              accepted for backwards compatibility.

       mibAllowUnderline (1|yes|true|0|no|false)
              whether to allow underline characters in MIB object names and  enumeration  values.
              This token can be used to accept such (strictly incorrect) MIBs.

       mibWarningLevel INTEGER
              the minimum warning level of the warnings printed by the MIB parser.

OUTPUT CONFIGURATION

       logTimestamp (1|yes|true|0|no|false)
              Whether the commands should log timestamps with their error/message logging or not.
              Note that output will not look as pretty with timestamps if the source code that is
              doing  the  logging does incremental logging of messages that are not line buffered
              before being passed to the logging routines.  This option is only  used  when  file
              logging is active.

       printNumericEnums (1|yes|true|0|no|false)
              Equivalent to -Oe.

       printNumericOids (1|yes|true|0|no|false)
              Equivalent to -On.

       dontBreakdownOids (1|yes|true|0|no|false)
              Equivalent to -Ob.

       escapeQuotes (1|yes|true|0|no|false)
              Equivalent to -OE.

       quickPrinting (1|yes|true|0|no|false)
              Equivalent to -Oq.

       printValueOnly (1|yes|true|0|no|false)
              Equivalent to -Ov.

       dontPrintUnits (1|yes|true|0|no|false)
              Equivalent to -OU.

       numericTimeticks (1|yes|true|0|no|false)
              Equivalent to -Ot.

       printHexText (1|yes|true|0|no|false)
              Equivalent to -OT.

       hexOutputLength integer
              Specifies where to break up the output of hexadecimal strings.  Set to 0 to disable
              line breaks.  Defaults to 16.

       suffixPrinting (0|1|2)
              The value 1 is equivalent to -Os and the value 2 is equivalent to -OS.

       oidOutputFormat (1|2|3|4|5|6)
              Maps -O options as follow: -Os=1, -OS=2, -Of=3, -On=4, -Ou=5.  The value 6  has  no
              matching -O option. It suppresses output.

       extendedIndex (1|yes|true|0|no|false)
              Equivalent to -OX.

       noDisplayHint (1|yes|true|0|no|false)
              Disables  the  use  of  DISPLAY-HINT information when parsing indices and values to
              set. Equivalent to -Ih.

       outputPrecision PRECISION
              Uses the PRECISION string to allow modification of the  value  output  format.  See
              snmpcmd(1)  for details.  Equivalent to -Op (which takes precedence over the config
              file).

FILES

       System-wide configuration files:
              /etc/snmp/snmp.conf
              /etc/snmp/snmp.local.conf

       User-specific configuration settings:
              $HOME/.snmp/snmp.conf
              $HOME/.snmp/snmp.local.conf

       Destination host specific files:
              /etc/snmp/hosts/HOSTNAME.conf
              $HOME/.snmp/hosts/HOSTNAME.conf