SNMP.CONF(5) Net-SNMP SNMP.CONF(5)
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 con-trol control
trol 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.
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.
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.
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 equiv-alent equivalent
alent 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.
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 house-keeping. housekeeping.
keeping.
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 appli-cation application
cation 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 back-wards. backwards.
wards. 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.
SNMPv3 SETTINGS
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
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 nor-mally normally
mally 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 suit-able suitable
able 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).
SERVER BEHAVIOUR
persistentDir DIRECTORY
defines the directory where snmpd and snmptrapd store persistent configuration settings.
If not specified, the persistent directory defaults to /var/db/net-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 persist-ing persisting
ing 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 housekeep-ing. housekeeping.
ing.
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.
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.
strictCommentTerm (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 is poorly named, since a value of "true" will turn off the strict
interpretation of MIB comments.
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. Equiva-lent Equivalent
lent to -Ih.
FILES
/etc/snmp/snmp.conf, /etc/snmp/snmp.local.conf - common configuration settings
~/.snmp/snmp.conf - user-specific configuration settings
SEE ALSO
snmp_config(5), read_config(3), snmpcmd(1).
4th Berkeley Distribution 29 Jun 2005 SNMP.CONF(5)
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