omsnmp: SNMP Trap Output Module¶

Module Name:	omsnmp
Author:	Andre Lorbach <alorbach@adiscon.com>

Purpose¶

Provides the ability to send syslog messages as an SNMPv1 & v2c traps. By default, SNMPv2c is preferred. The syslog message is wrapped into a OCTED STRING variable. This module uses the NET-SNMP library. In order to compile this module, you will need to have the NET-SNMP developer (headers) package installed.

Configuration Parameters¶

Note

Parameter names are case-insensitive.

Action Parameters¶

Server¶

type	default	mandatory	`obsolete legacy` directive
string	none	yes	`$actionsnmptarget`

This can be a hostname or ip address, and is our snmp target host. This parameter is required, if the snmptarget is not defined, nothing will be send.

Port¶

type	default	mandatory	`obsolete legacy` directive
integer	162	no	`$actionsnmptargetport`

The port which will be used, common values are port 162 or 161.

Transport¶

type	default	mandatory	`obsolete legacy` directive
string	udp	no	`$actionsnmptransport`

Defines the transport type you wish to use. Technically we can support all transport types which are supported by NET-SNMP. To name a few possible values: udp, tcp, udp6, tcp6, icmp, icmp6 …

Version¶

type	default	mandatory	`obsolete legacy` directive
integer	1	no	`$actionsnmpversion`

There can only be two choices for this parameter for now. 0 means SNMPv1 will be used. 1 means SNMPv2c will be used. Any other value will default to 1.

Community¶

type	default	mandatory	`obsolete legacy` directive
string	public	no	`$actionsnmpcommunity`

This sets the used SNMP Community.

TrapOID¶

type	default	mandatory	`obsolete legacy` directive
string	1.3.6.1.4.1.19406.1.2.1	no	`$actionsnmptrapoid`

The default value means “ADISCON-MONITORWARE-MIB::syslogtrap”.

This configuration parameter is used for SNMPv2 only. This is the OID which defines the trap-type, or notification-type rsyslog uses to send the trap. In order to decode this OID, you will need to have the ADISCON-MONITORWARE-MIB and ADISCON-MIB mibs installed on the receiver side. Downloads of these mib files can be found here:

https://www.adiscon.org/download/ADISCON-MIB.txt

https://www.adiscon.org/download/ADISCON-MONITORWARE-MIB.txt Thanks to the net-snmp mailinglist for the help and the recommendations ;).

MessageOID¶

type	default	mandatory	`obsolete legacy` directive
string	1.3.6.1.4.1.19406.1.2.1	no	`$actionsnmpsyslogmessageoid`

This OID will be used as a variable, type “OCTET STRING”. This variable will contain up to 255 characters of the original syslog message including syslog header. It is recommend to use the default OID. In order to decode this OID, you will need to have the ADISCON-MONITORWARE-MIB and ADISCON-MIB mibs installed on the receiver side. To download these custom mibs, see the description of TrapOID.

EnterpriseOID¶

type	default	mandatory	`obsolete legacy` directive
string	1.3.6.1.4.1.3.1.1	no	`$actionsnmpenterpriseoid`

The default value means “enterprises.cmu.1.1”

Customize this value if needed. I recommend to use the default value unless you require to use a different OID. This configuration parameter is used for SNMPv1 only. It has no effect if SNMPv2 is used.

SpecificType¶

type	default	mandatory	`obsolete legacy` directive
integer	0	no	`$actionsnmpspecifictype`

This is the specific trap number. This configuration parameter is used for SNMPv1 only. It has no effect if SNMPv2 is used.

Snmpv1DynSource¶

type	default	mandatory	`obsolete legacy` directive
string		no	none

Added in version 8.2001.

If set, the source field of the SNMP trap can be overwritten with the a template. The internal default is “%fromhost-ip%”. The result should be a valid IPv4 Address. Otherwise setting the source will fail.

Below is a sample template called “dynsource” which you can use to set the source to a custom property:

set $!custom_host = $fromhost;
template(name="dynsource" type="list") {
     property(name="$!custom_host")
}

This configuration parameter is used for SNMPv1 only. It has no effect if SNMPv2 is used.

TrapType¶

type	default	mandatory	`obsolete legacy` directive
integer	6	no	`$actionsnmptraptype`

There are only 7 Possible trap types defined which can be used here. These trap types are:

= SNMP_TRAP_COLDSTART
= SNMP_TRAP_WARMSTART
= SNMP_TRAP_LINKDOWN
= SNMP_TRAP_LINKUP
= SNMP_TRAP_AUTHFAIL
= SNMP_TRAP_EGPNEIGHBORLOSS
= SNMP_TRAP_ENTERPRISESPECIFIC

Note

Any other value will default to 6 automatically. This configuration parameter is used for SNMPv1 only. It has no effect if SNMPv2 is used.

Caveats/Known Bugs¶

In order to decode the custom OIDs, you will need to have the adiscon mibs installed.

Examples¶

Sending messages as snmp traps¶

The following commands send every message as a snmp trap.

module(load="omsnmp")
action(type="omsnmp" server="localhost" port="162" transport="udp"
       version="1" community="public")

Support: rsyslog Assistant | GitHub Discussions | GitHub Issues: rsyslog source project

Contributing: Source & docs: rsyslog source project