By: Sweta Dargad

*All About SNMP

*Popularity

*SNMP has become the most popular network management protocol for its simplicity and scalability.

*Simple Network Management Protocol (SNMP) is commonly used within NMS(Network Monitoring System)

*Tools like Cacti and OP Manager use SNMP for querying devices.

*SNMP is the de-facto standard for Network Monitoring.

*SNMP is integrated into most of devices like routers, switches, servers and workstations.

*SNMP Versions

*SNMPv1 :Simple Network Management Protocol (RFC1213)has MIB2

*SNMPv2c: (RFC1907) includes security, confidentiality

*SNMPv3 :(RFC2275)addition of cryptographic security ensures confidentiality, integrity and authentication

*It is Internet-standard protocol for managing devices on IP networks

*community Strings :Read Only and Read write

*Overview of SNMP

Architecture

*An SNMP-managed network includes management stations and network devices

*Agent software which runs on managed devices

*Network management system (NMS) software which runs on the manager

*MIB (Management Information Base), can monitor the state of hardware and software, and the running state of the system.

*SNMP based Network Monitoring

SNMP sends and receives information on port UDP 161 and 162

*MIB tree

The collection of objects is referred to as managementinformation bases (MIB)This MIB tree gives the OId(Object Id)

*The SNMP-based management model

* Flow of commands between the SNMP manager and

SNMP device

*Overview of Net-SNMP

*Net-SNMP is a suite of applications used to implement

*SNMPv1, SNMPv2c and SNMPv3 using both IPv4 and IPv6

*A library for developing new SNMP applications, with both C and perl APIs

*Information from snmp enabled device is collected by commands like

• snmpget

• snmpgetnext

• snmpwalk

• snmpset

• snmptrap

*SNMP Commands

1. Snmpget: request to query for information on a network entity

Eg: snmpget -v1 -c public localhost system.sysUpTime

Or snmpget –v1 –c private 127.0.0.1 1.3.6.1.2.1.1.3

Here system.sysUpTime is named OId of 1.3.6.1.2.1.1.3 which be can get by

2. snmptranslate 1.3.6.1.2.1.1.3 and vice-versa.

Similarly

3. snmpwalk:  is an SNMP application that uses SNMP GETNEXT requests to query a network entity for a tree of information.

4. snmpset: is used to set the information from users terminal