# 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:

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

http://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

New 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 canm 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:

    0 = SNMP_TRAP_COLDSTART
    1 = SNMP_TRAP_WARMSTART
    2 = SNMP_TRAP_LINKDOWN
    3 = SNMP_TRAP_LINKUP
    4 = SNMP_TRAP_AUTHFAIL
    5 = SNMP_TRAP_EGPNEIGHBORLOSS
    6 = 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")

See also

Help with configuring/using `Rsyslog`:

- Mailing list - best route for general questions

- GitHub: rsyslog source project - detailed questions, reporting issues that are believed to be bugs with `Rsyslog`

See also

Contributing to `Rsyslog`:

- Source project: rsyslog project README.

- Documentation: rsyslog-doc project README

Copyright 2008-2023 Rainer Gerhards (Großrinderfeld), and Others.