snmptrapd - Receive and log SNMP trap messages.
snmptrapd [OPTIONS] [LISTENING ADDRESSES]
snmptrapd is an SNMP application that receives and logs SNMP TRAP and
Note: the default is to listen on UDP port 162 on all IPv4 interfaces.
Since 162 is a privileged port, snmptrapd must typically be run as
-a Ignore authenticationFailure traps.
-A Append to the log file rather than truncating it.
Note that this needs to come before any -Lf options that it
should apply to.
-c FILE Read FILE as a configuration file.
-C Do not read any configuration files except the one optionally
specified by the -c option.
-d Dump (in hexadecimal) the sent and received SNMP packets.
Turn on debugging output for the given TOKEN(s). Try ALL for
extremely verbose output.
-e Print event numbers (rising/falling alarm etc.) from the
This functionality is being deprecated and will be removed in
-f Do not fork() from the calling shell.
When logging to standard output, use the format in the string
FORMAT. See the section FORMAT SPECIFICATIONS below for more
Display a brief usage message and then exit.
-H Display a list of configuration file directives understood by
the trap daemon and then exit.
Specifies which modules should (or should not) be initialized
when snmptrapd starts up. If the comma-separated INITLIST is
preceded with a '-', it is the list of modules that should not
be started. Otherwise this is the list of the only modules
that should be started.
To get a list of compiled modules, run snmptrapd with the
arguments -Dmib_init -H (assuming debugging support has been
Specify where logging output should be directed (standard error
or output, to a file or via syslog). See LOGGING OPTIONS in
snmpcmd(1) for details.
Specifies a colon separated list of MIB modules to load for
this application. This overrides the environment variable
MIBS. See snmpcmd(1) for details.
Specifies a colon separated list of directories to search for
MIBs. This overrides the environment variable MIBDIRS. See
snmpcmd(1) for details.
-n Do not attempt to translate source addresses of incoming
packets into hostnames.
-p FILE Save the process ID of the trap daemon in FILE.
Specifies how MIB objects and other output should be displayed.
See the section OUTPUT OPTIONS in the snmpcmd(1) manual page
-t Do not log traps to syslog. This disables logging to syslog.
This is useful if you want the snmptrapd application to only
run traphandle hooks and not to log any traps to any location.
Print version information for the trap daemon and then exit.
Connect to the AgentX master agent on the specified address,
rather than the default "/var/agentx/master". See snmpd(8) for
details of the format of such addresses.
Allows to specify any token ("name") supported in the
snmptrapd.conf file and sets its value to "value". Overrides
the corresponding token in the snmptrapd.conf file. See
snmptrapd.conf(5) for the full list of tokens.
snmptrapd interprets format strings similarly to printf(3). It
understands the following formatting sequences:
%% a literal %
%a the contents of the agent-addr field of the PDU (v1 TRAPs only)
%A the hostname corresponding to the contents of the agent-addr
field of the PDU, if available, otherwise the contents of the
agent-addr field of the PDU (v1 TRAPs only).
%b PDU source address (Note: this is not necessarily an IPv4
%B PDU source hostname if available, otherwise PDU source address
(see note above)
%h current hour on the local system
%H the hour field from the sysUpTime.0 varbind
%j current minute on the local system
%J the minute field from the sysUpTime.0 varbind
%k current second on the local system
%K the seconds field from the sysUpTime.0 varbind
%l current day of month on the local system
%L the day of month field from the sysUpTime.0 varbind
%m current (numeric) month on the local system
%M the numeric month field from the sysUpTime.0 varbind
%N enterprise string
%q trap sub-type (numeric, in decimal)
%P security information from the PDU (community name for v1/v2c,
user and context for v3)
%t decimal number of seconds since the operating system epoch (as
returned by time(2))
%T the value of the sysUpTime.0 varbind in seconds
%v list of variable-bindings from the notification payload. These
will be separated by a tab, or by a comma and a blank if the
alternate form is requested See also %V
%V specifies the variable-bindings separator. This takes a
sequence of characters, up to the next % (to embed a % in the
string, use \%)
%w trap type (numeric, in decimal)
%W trap description
%y current year on the local system
%Y the year field from the sysUpTime.0 varbind
In addition to these values, an optional field width and precision may
also be specified , just as in printf(3), and a flag value. The
following flags are supported:
- left justify
0 use leading zeros
# use alternate form
The "use alternate form" flag changes the behavior of various format
Time information will be displayed based on GMT (rather than the
The variable-bindings will be a comma-separated list (rather
than a tab-separated one)
The system uptime will be broken down into a human-meaningful
format (rather than being a simple integer)
To get a message like "14:03 TRAP3.1 from humpty.ucd.edu" you could use
something like this:
snmptrapd -P -F "%02.2h:%02.2j TRAP%w.%q from %A\n"
If you want the same thing but in GMT rather than local time, use
snmptrapd -P -F "%#02.2h:%#02.2j TRAP%w.%q from %A\n"
By default, snmptrapd listens for incoming SNMP TRAP and INFORM packets
on UDP port 162 on all IPv4 interfaces. However, it is possible to
modify this behaviour by specifying one or more listening addresses as
arguments to snmptrapd. See the snmpd(8) manual page for more
information about the format of listening addresses.
As of net-snmp 5.0, the snmptrapd application supports the
NOTIFICATION-LOG-MIB. It does this by opening an AgentX subagent
connection to the master snmpd agent and registering the notification
log tables. As long as the snmpd application is started first, it will
attach itself to it and thus you should be able to view the last
recorded notifications via the nlmLogTable and nlmLogVariableTable.
See the snmptrapd.conf file and the "dontRetainLogs" token for turning
off this support. See the NOTIFICATION-LOG-MIB for more details about
the MIB itself.
EXTENSIBILITY AND CONFIGURATION
See the snmptrapd.conf(5) manual page.
snmpcmd(1), snmpd(8), printf(3), snmptrapd.conf(5), syslog(8),