Simple Network Management Protocol (SNMP)

• First proposed in 1988
• Allows querying of information about networking devices, and can also allow users to update information
• Widely used in network monitoring
• Port 161

SNMP Versions

• 1.0 - Plain-text, no security/li>
• 2.0 - Some security introduced, but controversial
• 2.0c "Community" - Without controversial security
• 3.0 - Better security and authentication

In practice, most devices support many versions

SNMP Data

• The data is presented as variables
• Data can be read, and in some cases written
• Data is presented in a hierarchical structure
• Unfortunately the data can be hard to read:
• 1.3.6.1.2.1.5.8 = 123???

Management Information Base (MIB)

• SNMP does not define information
• Instead, it is defined in a management information base
• The MIBs may vary based on the device, but there are standards available
• See http://www.simpleweb.org/ietf/mibs/

Protocol Data Units (PDU)

• GetRequest
• SetRequest
• GetNextRequest
• GetBulkRequest
• Response
• Trap
• InformRequest

Community String

• Acts as a rudimentary "password" when communicating
• In SNMPv1, transmitted as plaintext and easily sniffed
• When developed, security was not a concern

snmpget

snmpget -v 2c -c demopublic test.net-snmp.org SNMPv2-MIB::sysUpTime.0
SNMPv2-MIB::sysUpTime.0 = Timeticks: (586731977) 67 days, 21:48:39.77

Source: Wikipedia

snmpwalk

snmpwalk -t 5 -Os -c demopublic -v 2c test.net-snmp.org system
sysDescr.0 = STRING: Linux test.net-snmp.org 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009 x86_64
sysObjectID.0 = OID: netSnmpAgentOIDs.10
sysUpTimeInstance = Timeticks: (34198503) 3 days, 22:59:45.03
sysContact.0 = STRING: Net-SNMP Coders
sysName.0 = STRING: test.net-snmp.org
sysLocation.0 = STRING: Undisclosed

Source: Wikipedia

Assignments

• Lab 3 - Core Networking Services: Due Monday 2/27 10:30 AM