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200-301 Exam Prep

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1Networking Devices2Interfaces And Cables3OSI Model and TCP/IP Suite4Intro to the CLI5Ethernet LAN Switching - Part 16Ethernet LAN Switching - Part 27IPv4 Addressing - Part 18IPv4 Addressing - Part 29Switch Interfaces10The IPv4 Header11Routing Fundamentals - Part 111Static Routing - Part 212Life of a Packet13Subnetting - Part 114Subnetting - Part 215Subnetting (VLSM) - Part 316VLANs - Part 117VLANs - Part 218VLANs - Part 319DTP / VTP20Spanning Tree Protocol - Part 121Spanning Tree Protocol - Part 222Rapid Spanning Tree Protocol23Etherchannel24Dynamic Routing25RIP / EIGRP26OSPF - Part 127OSPF - Part 228OSPF - Part 329First Hop Redundancy Protocol30TCP and UDP31IPv6 - Part 132IPv6 - Part 233IPv6 - Part 334Standard Access Control List35Extended Access Control List36CDP and LLDP37NTP - Network Time Protocol38DNS - Domain Name System39DHCP - Dynamic Host Configuration Protocol40SNMP - Simple Network Management Protocol41SYSLOG42SSH - Secure Shell43FTP and TFTP44NAT (Static) - Part 145NAT (Dynamic) - Part 246QoS (Voice VLAN) - Part 147QoS (Quality of Service) - Part 248Security Fundamentals49Port Security50DHCP Snooping51Dynamic ARP Inspection52LAN Architectures53WAN Architectures54Virtualization and Cloud - Part 154Virtualization (Containers) - Part 254Virtualization (VRF) - Part 355Wireless Fundamentals56Wireless Architectures57Wireless Security58Wireless Configuration59Introduction to Network Automation60JSON, XML, and YAML61REST APIs62Software Defined Networking63Ansible, Puppet, and Chef67CCNA Complete Cheatsheet
/SNMP - Simple Network Management Protocol
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SNMP - Simple Network Management Protocol

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40. SNMP (Simple Network Management Protocol)

SNMP OVERVIEW

  • SNMP is an INDUSTRY-STANDARD FRAMEWORK and PROTOCOL that was originally released in 1988

These RFCs make up SNMPv1 (Do not need to memorize)

Code
RFC 1065 - Structure and identification of management information for TCP/IP based internets
RFC 1066 - Management information base for network management of TCP/IP based internets
RFC 1067 - A simple network management protocol
  • Don’t let the ‘Simple’ in the name fool you !
  • SNMP can be used to monitor the STATUS of DEVICES, make CONFIGURATION CHANGES, etc.
  • There are TWO MAIN TYPES of DEVICES in SNMP:
    • MANAGED DEVICES
      • These are the DEVICES being managed using SNMP
        • Ex: ROUTERS, SWITCHES
    • NETWORK MANAGEMENT STATION (NMS)
      • The DEVICE / DEVICES managing the MANAGED DEVICES
      • THIS is the SNMP ‘SERVER’

SMNP OPERATIONS

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SMNP COMPONENTS

OVERVIEW

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NMS

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MANAGED DEVICES

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SNMP OIDs

  • SNMP Object IDs are ORGANIZED in a HIERARCHICAL STRUCTURE

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SNMP VERSIONS

  • Many versions of SNMP have been proposed/developed, however, only three major versions have achieved wide-spread use:

  • SNMPv1

    • The ORIGINAL version of SNMP

  • SNMPv2c

    • Allows the NMS to retrieve LARGE AMOUNTS of information in a SINGLE REQUEST, so it is more efficient
    • ‘c’ refers to the ‘community strings’ used as PASSWORDS in SNMPv1, removed from SNMPv2, and then added BACK for SNMPv2

  • SNMPv3

    • A much more SECURE version of SNMP that supports STRONG ENCRYPTION and AUTHENTICATION.

      <aside> 💡 WHENEVER POSSIBLE, this version should be used! </aside>

SNMP MESSAGES

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  1. SNMP READ

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  1. SMNP WRITE

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  1. SNMP NOTIFICATION

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SNMP AGENT listens for MESSAGES on UDP Port 161

SNMP MANAGER listens for MESSAGES on UDP Port 162

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SNMPv2c CONFIGURATION (Basic)

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WHAT HAPPENS WITH R1’s G0/1 INTERFACE GOES DOWN?

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NOTE:

UDP message sent to Destination Port 162 (SNMP Manager)

“version” is set to v2c

community is “Jeremy1” (Read Only - no Set messages)

snmpV2-trap : trap message sent due to interface G0/1 going down

variable-bindings : contains the OID sent to identify the issue.

SNMP SUMMARY

  • SNMP helps MANAGE DEVICES over a NETWORK

  • MANAGED DEVICES are the devices being managed using SNMP (such as ROUTERS, SWITCHES, FIREWALLS)

  • NETWORK MANAGEMENT STATIONS (NMS) are the SNMP “servers” that manage the devices

    • NMS receives notifications from Managed Devices
    • NMS changes settings on Managed Devices
    • NMS checks status of Managed Devices

  • Variables, such as Interface Status, Temperature, Traffic Load, Hostname, etc are STORED in the MANAGMENT INFORMATION BASE (MIB) and identified using Object IDs (OIDs)

Main SNMP versions : SNMPv1, SNMPv2c, SNMPv3

Code
SNMP MESSAGES : 
* Get / GetNext / GetBulk
* Set
* Trap
* Inform
* Response
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