SNMPTRAPD.CONF(5) Net-SNMP SNMPTRAPD.CONF(5)
NAME
snmptrapd.conf - configuration file for the Net-SNMP notification
receiver
DESCRIPTION
The Net-SNMP notification receiver (trap daemon) uses one or more con
figuration files to control its operation and how incoming traps (and
INFORM requests) should be processed. This file (snmptrapd.conf) can
be located in one of several locations, as described in the snmp_con
fig(5) manual page.
IMPORTANT
Previously, snmptrapd would accept all incoming notifications, and log
them automatically (even if no explicit configuration was provided).
Starting with release 5.3, access control checks will be applied to
incoming notifications. If snmptrapd is run without a suitable configu
ration file (or equivalent access control settings), then such traps
WILL NOT be processed. See the section ACCESS CONTROL for more
details.
As with the agent configuration, the snmptrapd.conf directives can be
divided into four distinct groups.
TRAPD BEHAVIOUR
snmpTrapdAddr [:][,...]
defines a list of listening addresses, on which to receive
incoming SNMP notifications. See the section LISTENING
ADDRESSES in the snmpd(8) manual page for more information about
the format of listening addresses.
The default behaviour is to listen on UDP port 162 on all IPv4
interfaces.
doNotRetainNotificationLogs yes
disables support for the NOTIFICATION-LOG-MIB. Normally the
snmptrapd program keeps a record of the traps received, which
can be retrieved by querying the nlmLogTable and nlmLogvari
ableTable tables. This directive can be used to suppress this
behaviour.
See the snmptrapd(8) manual page and the NOTIFICATION-LOG-MIB
for details.
doNotLogTraps yes
disables the logging of notifications altogether. This is use
ful if the snmptrapd application should only run traphandle
hooks and should not log traps to any location.
doNotFork yes
do not fork from the calling shell.
pidFile PATH
defines a file in which to store the process ID of the notifica
tion receiver. By default, this ID is not saved.
ACCESS CONTROL
Starting with release 5.3, it is necessary to explicitly specify who is
authorised to send traps and informs to the notification receiver (and
what types of processing these are allowed to trigger). This uses an
extension of the VACM model, used in the main SNMP agent.
There are currently three types of processing that can be specified:
log log the details of the notification - either in a speci
fied file, to standard output (or stderr), or via syslog
(or similar).
execute
pass the details of the trap to a specified handler pro
gram, including embedded perl.
net forward the trap to another notification receiver.
In the following directives, TYPES will be a (comma-separated) list of
one or more of these tokens. Most commonly, this will typically be
log,execute,net to cover any style of processing for a particular cate
gory of notification. But it is perfectly possible (even desirable) to
limit certain notification sources to selected processing only.
authCommunity TYPES COMMUNITY [SOURCE [OID | -v VIEW ]]
authorises traps (and SNMPv2c INFORM requests) with the speci
fied community to trigger the types of processing listed. By
default, this will allow any notification using this community
to be processed. The SOURCE field can be used to specify that
the configuration should only apply to notifications received
from particular sources - see snmpd.conf(5) for more details.
authUser TYPES [-s MODEL] USER [LEVEL [OID | -v VIEW ]]
authorises SNMPv3 notifications with the specified user to trig
ger the types of processing listed. By default, this will
accept authenticated requests. (authNoPriv or authPriv). The
LEVEL field can be used to allow unauthenticated notifications
(noauth), or to require encryption (priv), just as for the SNMP
agent.
With both of these directives, the OID (or -v VIEW) field can be
used to retrict this configuration to the processing of particu
lar notifications.
Note: Unlike the VACM processing described in RFC 3415, this
view is only matched against the snmpTrapOID value of the
incoming notification. It is not applied to the payload
varbinds held within that notification.
authGroup TYPES [-s MODEL] GROUP [LEVEL [OID | -v VIEW ]]
authAccess TYPES [-s MODEL] GROUP VIEW [LEVEL [CONTEXT]]
setAccess GROUP CONTEXT MODEL LEVEL PREFIX VIEW TYPES
authorise notifications in the specified GROUP (configured using
the group directive) to trigger the types of processing listed.
See snmpd.conf(5) for more details.
createUser username (MD5|SHA) authpassphrase [DES|AES]
See the snmpd.conf(5) manual page for a description of how to
create SNMPv3 users. This is roughly the same, but the file
name changes to snmptrapd.conf from snmpd.conf.
disableAuthorization yes
will disable the above access control checks, and revert to the
previous behaviour of accepting all incoming notifications.
LOGGING
format1 FORMAT
format2 FORMAT
specify the format used to display SNMPv1 TRAPs and SNMPv2 noti
fications respectively. Note that SNMPv2c and SNMPv3 both use
the same SNMPv2 PDU format.
See snmptrapd(8) for the layout characters available.
ignoreAuthFailure yes
instructs the receiver to ignore authenticationFailure traps.
Note: This currently only affects the logging of such notifica
tions. authenticationFailure traps will still be passed
to trap handler scripts, and forwarded to other notifica
tion receivers. This behaviour should not be relied on,
as it is likely to change in future versions.
logOption string
specifies where notifications should be logged - to standard
output, standard error, a specified file or via syslog. See the
section LOGGING OPTIONS in the snmpcmd(1) manual page for
details.
outputOption string
specifies various characteristics of how OIDs and other values
should be displayed. See the section OUTPUT OPTIONS in the snm
pcmd(1) manual page for details.
printEventNumbers yes
enables specialised logging of event-related notifications from
the (long obsolete) M2M-MIB.
NOTIFICATION PROCESSING
As well as logging incoming notifications, they can also be forwarded
on to another notification receiver, or passed to an external program
for specialised processing.
traphandle OID|default PROGRAM [ARGS ...]
invokes the specified program (with the given arguments) when
ever a notification is received that matches the OID token. For
SNMPv2c and SNMPv3 notifications, this token will be compared
against the snmpTrapOID value taken from the notification. For
SNMPv1 traps, the generic and specific trap values and the
enterprise OID will be converted into the equivalent OID (fol
lowing RFC 2576).
Typically, the OID token will be the name (or numeric OID) of a
NOTIFICATION-TYPE object, and the specified program will be
invoked for notifications that match this OID exactly. However
this token also supports a simple form of wildcard suffixing.
By appending the character notification based within subtree
rooted at the specified OID. For example, an OID token of
.1.3.6.1.4.1* would match any enterprise specific notification
(including the specified OID itself). An OID token of
.1.3.6.1.4.1.* would would work in much the same way, but would
not match this exact OID - just notifications that lay strictly
below this root. Note that this syntax does not support full
regular expressions or wildcards - an OID token of the form
oid.*.subids is not valid.
If the OID field is the token default then the program will be
invoked for any notification not matching another (OID specific)
traphandle entry.
Details of the notification are fed to the program via its standard
input. Note that this will always use the SNMPv2-style notification
format, with SNMPv1 traps being converted as per RFC 2576, before being
passed to the program. The input format is as follows, one entry per
line:
HOSTNAME
The name of the host that sent the notification, as
determined by gethostbyaddr(3).
IPADDRESS
The IP address of the host that sent the notification.
VARBINDS
A list of variable bindings describing the contents of
the notification, one per line. The first token on each
line (up until a space) is the OID of the varind, and the
remainder of the line is its value. The format of both
of these are controlled by the outputOption directive (or
similar configuration).
The first OID should always be SNMPv2-MIB::sysUpTime.0,
and the second should be SNMPv2-MIB::snmpTrapOID.0. The
remaining lines will contain the payload varbind list.
For SNMPv1 traps, the final OID will be
SNMPv2-MIB::snmpTrapEnterprise.0.
Example:
A traptoemail script has been included in the Net-SNMP
package that can be used within a traphandle directive:
traphandle default /usr/bin/perl /usr/bin/traptoemail -s
mysmtp.somewhere.com -f admin@somewhere.com me@some
where.com
forward OID|default DESTINATION
forwards notifications that match the specified OID to another
receiver listening on DESTINATION. The interpretation of OID
(and default) is the same as for the traphandle directive).
See the section LISTENING ADDRESSES in the snmpd(8) manual page
for more information about the format of listening addresses.
NOTES
o The daemon blocks while executing the traphandle commands.
(This should be fixed in the future with an appropriate signal
catch and wait() combination).
o All directives listed with a value of "yes" actually accept a
range of boolean values. These will accept any of 1, yes or
true to enable the corresponding behaviour, or any of 0, no or
false to disable it. The default in each case is for the fea
ture to be turned off, so these directives are typically only
used to enable the appropriate behaviour.
FILES
/etc/snmp/snmptrapd.conf
SEE ALSO
snmp_config(5), snmptrapd(8), syslog(8), variables(5), snmpd.conf(5),
read_config(3).
4th Berkeley Distribution 29 Jun 2005 SNMPTRAPD.CONF(5)
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