`SNMP` Library for Ruby¶ ↑

Summary¶ ↑

This library implements SNMP (the Simple Network Management Protocol). It is implemented in pure Ruby, so there are no dependencies on external libraries like net-snmp. You can run this library anywhere that Ruby can run.

This release supports the following:

The GetRequest, GetNextRequest, GetBulkRequest, SetRequest, Response SNMPv1_Trap, SNMPv2_Trap, and Inform PDUs
All of the ASN.1 data types defined by SNMPv1 and SNMPv2c
Sending informs and v1 and v2 traps
Trap handling for informs and v1 and v2 traps
Symbolic OID values (ie. “ifTable” instead of “1.3.6.1.2.1.2.2”) as

parameters to the SNMP::Manager API
Includes symbol data files for all current IETF MIBs
Compatible with Ruby 1.9 and higher

See the SNMP::Manager, SNMP::TrapListener, and SNMP::MIB classes and the examples below for more details.

Installation¶ ↑

You can use RubyGems to install the latest version of the SNMP library.

gem install snmp

Examples¶ ↑

Get Request¶ ↑

Retrieve a system description.

require 'snmp'

SNMP::Manager.open(:host => 'localhost') do |manager|
    response = manager.get(["sysDescr.0", "sysName.0"])
    response.each_varbind do |vb|
        puts "#{vb.name.to_s}  #{vb.value.to_s}  #{vb.value.asn1_type}"
    end
end

Set Request¶ ↑

Create a varbind for setting the system name.

require 'snmp'
include SNMP

manager = Manager.new(:host => 'localhost')
varbind = VarBind.new("1.3.6.1.2.1.1.5.0", OctetString.new("My System Name"))
manager.set(varbind)
manager.close

Table Walk¶ ↑

Walk the ifTable.

require 'snmp'

ifTable_columns = ["ifIndex", "ifDescr", "ifInOctets", "ifOutOctets"]
SNMP::Manager.open(:host => 'localhost') do |manager|
    manager.walk(ifTable_columns) do |row|
        row.each { |vb| print "\t#{vb.value}" }
        puts
    end
end

Get-Next Request¶ ↑

A more difficult way to walk the ifTable.

require 'snmp'
include SNMP

Manager.open(:host => 'localhost') do |manager|
    ifTable = ObjectId.new("1.3.6.1.2.1.2.2")
    next_oid = ifTable
    while next_oid.subtree_of?(ifTable)
        response = manager.get_next(next_oid)
        varbind = response.varbind_list.first
        next_oid = varbind.name
        puts varbind.to_s
    end
end

Get-Bulk Request¶ ↑

Get interface description and admin status for 10 rows of the ifTable.

require 'snmp'
include SNMP

ifDescr_OID = ObjectId.new("1.3.6.1.2.1.2.2.1.2")
ifAdminStatus_OID = ObjectId.new("1.3.6.1.2.1.2.2.1.7")
MAX_ROWS = 10
Manager.open(:host => 'localhost') do |manager|
    response = manager.get_bulk(0, MAX_ROWS, [ifDescr_OID, ifAdminStatus_OID])
    list = response.varbind_list
    until list.empty?
        ifDescr = list.shift
        ifAdminStatus = list.shift
        puts "#{ifDescr.value}    #{ifAdminStatus.value}"
    end
end

Trap Handling¶ ↑

Log traps to STDOUT.

require 'snmp'
require 'logger'

log = Logger.new(STDOUT)
m = SNMP::TrapListener.new do |manager|
    manager.on_trap_default do |trap|
        log.info trap.inspect
    end
end
m.join

Changes¶ ↑

Changes for version 1.3.2:

Accept non-standard error status codes

Changes for version 1.3.1:

Cleaned up deprecation warnings
Fixed SNMP::Integer#<=> method for Ruby 2.3.0 and later
Removed artificial limit on number of non-repeaters for GetBulkRequest
SNMP::BER module no longer pollutes global namespace

Changes for version 1.2.0:

Removed support for Ruby 1.8
Changed license to MIT License

Changes for version 1.1.1:

Incorporate various small pull requests

Changes for version 1.1.0:

Added MIB support to ObjectId and Varbind, so that to_s can return symbolic information
Added to_str method to ObjectId to return a numeric OID string (old to_s behavior)
TrapListener can now support multiple community strings

Changes for version 1.0.4:

New option handling and added lower-case versions of all options
Added SNMP::VERSION constant
Experimental support for IPv6
Removed support for installation with setup.rb

Changes for version 1.0.3:

Minor changes to Manager class. The :Transport option may now be an object or a class. Explicity call Timeout.timeout so that a timeout method may be defined in subclasses. Thanks to Eric Monti.

Changes for version 1.0.2:

Internal code changes to make this library compatible with both Ruby 1.8 and Ruby 1.9. Note that an ord() method is now added to the Fixnum class for Ruby 1.8. See the ber.rb file for details.

Changes for version 1.0.1:

Made the host configurable for the TrapListener. Previously defaulted to ‘localhost’.

Changes for version 1.0.0:

Added to_s method to TimeTicks. Displays time in human-readable form instead of just a number. The to_i method can still be used to get the number of ticks.

License¶ ↑

This SNMP Library is released under the MIT License.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

SNMP Library for Ruby¶ ↑