CCNA 200-301 Portable Command Guide, 6th Edition

The CCNA 200-301 Portable Command Guide summarizes all Cisco CCNA 201-301 certification-level Cisco IOS Software commands, keywords, command arguments, and associated prompts, providing you with tips and examples of how to apply the commands to real-world scenarios. Throughout, configuration examples give you a better understanding of how these commands are used in simple network designsand its portable enough to use whether youre in the server room or the equipment closet.

This edition has been fully updated to reflect the latest Cisco CCNA 200-301 certification objectives and new technologies shaping todays enterprise networks, including automation, programmability, and security-driven design. Whether youre preparing for the exam or working in the field, youll find this guide an indispensable resource for verifying commands, recalling configuration steps, and applying Cisco best practices.

New and Updated Coverage Includes

• Network Fundamentals: IPv4/IPv6 addressing, subnetting, VLSM, summarization, cabling, interfaces, and CLI essentials
• LAN Switching Technologies: VLANs, trunking, inter-VLAN routing, STP, EtherChannel, CDP, LLDP, and verification commands
• Routing Technologies: Static and dynamic routing, single-area OSPFv2 and OSPFv3 configuration, route summarization, and neighbor adjacency
• IP Services: DHCP, NAT, NTP, SNMP, Syslog, and device management fundamentals
• Security Fundamentals: Secure device access, port security, ACLs, DHCP snooping, dynamic ARP inspection, and device hardening
• Wireless Technologies: WLAN configuration, security settings, and basic troubleshooting for access points

Key Features:

• Quick, portable reference for all CCNA-level Cisco IOS commands
• Logical topic organization for fast lookup and practical learning
• Real-world configuration examples and verification output
• Compact and durableideal for data centers, classrooms, or fieldwork
• Create Your Own Journal section for personalized notes and lab results
• Ideal for last-minute review before the CCNA exam

Table of Contents

Introduction
Part I: Network Fundamentals
Chapter 1 IPv4 AddressingHow It Works
What Are IPv4 Addresses Used For?
What Does an IPv4 Address Look Like?
Network and Subnetwork Masks
Ways to Write a Network or Subnet Mask
Network, Node, and Broadcast Addresses
Classes of IPv4 Addresses
Network vs. Node (Host) Bits
RFC (Private) 1918 Addresses
Local vs. Remote Addresses
Classless Addressing
Lessons Learned
Chapter 2 How to Subnet IPv4 Addresses
Subnetting a Class C Network Using Binary
Subnetting a Class B Network Using Binary
Binary ANDing
So Why AND?
Shortcuts in Binary ANDing
Chapter 3 Variable Length Subnet Masking (VLSM)
IP Subnet Zero
VLSM Example
Step 1: Determine How Many H Bits Will Be Needed to Satisfy the Largest Network
Step 2: Pick a Subnet for the Largest Network to Use
Step 3: Pick the Next Largest Network to Work With
Step 4: Pick the Third Largest Network to Work With
Step 5: Determine Network Numbers for Serial Links
Chapter 4 Route Summarization
Example for Understanding Route Summarization
Step 1: Summarize Winnipegs Routes
Step 2: Summarize Calgarys Routes
Step 3: Summarize Edmontons Routes
Step 4: Summarize Vancouvers Routes
Route Summarization and Route Flapping
Requirements for Route Summarization
Chapter 5 IPv6 AddressingHow It Works
IPv6: A Very Brief Introduction
What Does an IPv6 Address Look Like?
Reducing the Notation of an IPv6 Address
Rule 1: Omit Leading 0s
Rule 2: Omit All-0s Hextet
Combining Rule 1 and Rule 2
Prefix Length Notation
IPv6 Address Types
Unicast Addresses
Multicast Addresses
Anycast Addresses
Chapter 6 Cables and Connections
Connecting a Rollover (Console) Cable to Your Router or Switch
Using a USB Cable to Connect to Your Router or Switch
Configuring a Terminal Emulator
LAN Connections
Serial Cable Types
Which Cable to Use?
ANSI/TIA Cabling Standards
T568A Versus T568B Cables
Chapter 7 The Command-Line Interface
Shortcuts for Entering Commands
Using the Tab Key to Complete Commands
Console Error Messages
Using the Question Mark for Help
enable Command
exit Command
end Command
disable Command
logout Command
reload Command
Setup Mode
Keyboard Help
History Commands
terminal Commands
show Commands
Using the Pipe Parameter ( | ) with the show or more Commands
Using the no and default Forms of Commands
Part II: LAN Switching Technologies
Chapter 8 Configuring a Switch
Help Commands
Command Modes
Verifying Commands
Resetting Switch Configuration
Setting Host Names
Setting Passwords
Setting IP Addresses and Default Gateways
The Ethernet Management Port
Supported Features on the Ethernet Management Port
Configuring and Verifying the Ethernet Management Port
Setting Interface Descriptions
The mdix auto Command
Setting Duplex Operation
Setting Operation Speed
Setting the Maximum Aging Time of the MAC Table
Managing the MAC Address Table
Configuration Example
Chapter 9 VLANs
Creating Static VLANs
Creating Static VLANs Using VLAN Configuration Mode
Assigning Ports to VLANs
Using the range Command
Configuring a Voice VLAN
Verifying VLAN Information
Saving VLAN Configurations
Erasing VLAN Configurations
Shutting Down or Suspending VLANs
Configuration Example: VLANs
9200 Switch
Chapter 10 VLAN Trunking Protocol and Inter-VLAN Communication
Dynamic Trunking Protocol (DTP)
Setting the VLAN Encapsulation Type
VLAN Trunking Protocol (VTP)
Configuring a VTP Version 3 Primary Server
Verifying VTP
Inter-VLAN Communication Using an External Router: Router-on-a- Stick
Inter-VLAN Communication on a Layer 3 Switch Through a Switch Virtual Interface
The autostate command
Removing Layer 2 Switchport Capability of an Interface on a Layer 3 Switch
Configuring Inter-VLAN Communication on a Layer 3 Switch
Inter-VLAN Communication Tips
Configuration Example: Inter-VLAN Communication
ISP Router
CORP Router
L2Switch2 (Catalyst 9200)
L3Switch1 (Catalyst 9300)
L2Switch1 (Catalyst 9200)
Chapter 11 Spanning Tree Protocol
Spanning Tree Protocol Definition
Enabling Spanning Tree Protocol
Changing the Spanning-Tree Mode
Configuring the Root Switch
Configuring a Secondary Root Switch
Configuring the Switch Priority of a VLAN
Configuring Port Priority
Path Cost: Short vs. Long
Configuring the Path Cost
Configuring STP Timers
Configuring Optional Spanning-Tree Features
PortFast
BPDU Guard (2xxx/Older 3xxx Series)
BPDU Guard (3650/9xxx Series)
BPDU Filter
Root Guard
Enabling the Extended System ID
Verifying STP
Troubleshooting Spanning Tree Protocol
Configuration Example: PVST+
Core Switch (9300)
Distribution 1 Switch (9300)
Distribution 2 Switch (9300)
Access 1 Switch (9200)
Access 2 Switch (9200)
Chapter 12 EtherChannel
EtherChannel
Interface Modes in EtherChannel
Default EtherChannel Configuration
Guidelines for Configuring EtherChannel
Configuring Layer 2 EtherChannel
Configuring Layer 3 EtherChannel
Configuring EtherChannel Load Balancing
Configuring LACP Hot-Standby Ports
Monitoring and Verifying EtherChannel
Configuration Example: EtherChannel
DLSwitch (9300)
ALSwitch1 (9200)
ALSwitch2 (9200)
Chapter 13 Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP)
Cisco Discovery Protocol
Configuring CDP
Verifying and Troubleshooting CDP
CDP Design Tips
Link Layer Discovery Protocol (802.1AB)
Configuring LLDP (802.1AB)
Verifying and Troubleshooting LLDP
Part III: Routing Technologies
Chapter 14 Configuring a Cisco Router
Router Modes
Entering Global Configuration Mode
Configuring a Router Name
Configuring Passwords
Password Encryption
Interface Names
Moving Between Interfaces
Configuring a Serial Interface
Assigning an IPv4 Address to a Fast Ethernet Interface
Assigning an IPv4 Address to a Gigabit Ethernet Interface
Assigning IPv6 Addresses to Interfaces
Creating a Message-of-the-Day Banner
Creating a Login Banner
Mapping a Local Host Name to a Remote IP Address
The no ip domain-lookup Command
Working with DNS on a Router
The logging synchronous Command
The exec-timeout Command
Saving Configurations
Erasing Configurations
The write Command
Verifying Your Configurations Using show Commands
EXEC Commands in Configuration Mode: The do Command
Configuration Example: Basic Router Configuration
Boston Router
Buffalo Router
Chapter 15 Interpreting the Routing Table and Configuring Static Routes
Interpreting the Routing Table
Codes
The Default Route
The Default Route on a Client Machine
Routes
Configuring an IPv4 Static Route
Static Routes and Recursive Lookups
The permanent Keyword
Floating Static Routes and Administrative Distance
Configuring an IPv4 Default Route
Verifying IPv4 Static Routes
Configuration Example: IPv4 Static Routes
Ketchikan Router
Juneau Router
Sitka Router
Configuring an IPv6 Static Route
Floating Static Routes in IPv6
Configuring an IPv6 Default Route
Verifying IPv6 Static Routes
Chapter 16 Open Shortest Path First (OSPF)
OSPFv2 Versus OSPFv3
OSPF Network Types
Configuring OSPF
Using Wildcard Masks with OSPF Areas
Configuring OSPFv2 Using Interface Subcommands
Converting from Traditional Configuration to Interface Configuration Mode
Optimizing OSPF Parameters
Loopback Interfaces
Router ID
DR/BDR Elections
Timers
Propagating a Default Route
Verifying OSPFv2 Configurations
Troubleshooting OSPFv2
Configuration Example: Single-Area OSPF
Austin Router
Houston Router
Galveston Router
Part IV: IP Services
Chapter 17 DHCP
Configuring a DHCP Server on an IOS or IOS XE Router
Using Cisco IP Phones with a DHCP Server
Configuring DHCP Option 43 for Access Points
Verifying and Troubleshooting DHCP Configuration
Configuring a DHCP Helper Address
Configuring a DHCP Client on a Cisco IOS or IOS XE Software Ethernet Interface
Configuration Example: DHCP
Edmonton Router
Gibbons Router
Chapter 18 Network Address Translation (NAT)
Private IP Addresses: RFC 1918
Configuring Dynamic NAT: One Private to One Public Address Translation
Configuring PAT: Many Private to One Public Address Translation
Configuring Static NAT: One Private to One Permanent Public Address Translation
Verifying NAT and PAT Configurations
Troubleshooting NAT and PAT Configurations
Configuration Example: PAT
ISP Router
Company Router
Chapter 19 Configuring Network Time Protocol (NTP)
NTP Configuration
NTP Design
Securing NTP
Enabling NTP Authentication
Limiting NTP Access with Access Lists
Verifying and Troubleshooting NTP
Setting the Clock on a Router
Using Timestamps
Configuration Example: NTP
Core1 Router
Core2 Router
DLSwitch1
DLSwitch2
ALSwitch1
ALSwitch2
Part V: Security Fundamentals
Chapter 20 Layer Two Security Features
Setting Passwords on a Switch
Configuring Static MAC Addresses
Configuring Switch Port Security
Configuring Sticky MAC Addresses
Verifying Switch Port Security
Recovering Automatically from Error-Disabled Ports
Verifying Autorecovery of Error-Disabled Ports
Configuring DHCP Snooping
Verifying DHCP Snooping
Configuring Dynamic ARP Inspection (DAI)
Verifying Dynamic ARP Inspection
Configuration Example: Switch Security
Chapter 21 Managing Traffic Using Access Control Lists (ACLs)
Access List Numbers
Using Wildcard Masks
ACL Keywords
Creating Standard ACLs
Applying Standard ACLs to an Interface
Verifying ACLs
Removing ACLs
Creating Extended ACLs
Applying Extended ACLs to an Interface
The established Keyword
The log Keyword
Creating Named ACLs Using ACL Configuration Mode
Using Sequence Numbers in Named ACLs
Removing Specific Lines in Named ACLs Using Sequence Numbers
Sequence Number Tips
Including Comments in ACLs
Restricting Virtual Terminal Access
Tips for Configuring ACLs
Comparing ACLs in IOS and IOS XE
Using a Second (Common) Interface ACL in IOS XE
Matching Multiple Nonconsecutive Ports with eq in IOS XE
IPv6 ACLs
Verifying IPv6 ACLs
Configuration Examples: IPv4 ACLs
Configuration Examples: IPv6 ACLs
Chapter 22 Device Monitoring and Hardening
Device Monitoring
Configuration Backups
Implementing Logging
Configuring Syslog
Syslog Message Format
Syslog Severity Levels
Syslog Message Example
Device Hardening
Configuring Passwords
Password Encryption
Password Encryption Algorithm Types
Configuring the enable secret Password Using Encryption Algorithm Types
Configuring SSH
Verifying SSH
Restricting Virtual Terminal Access
Disabling Unneeded Services
Part VI: Infrastructure Management
Chapter 23 Troubleshooting and Verification
Viewing the Routing Table
Clearing the Routing Table
Determining the Gateway of Last Resort
Determining the Last Routing Update
Internet Control Message Protocol Redirect Messages
The ping Command
Examples of Using the ping and the Extended ping Commands
Interpreting the show interface Command
Clearing Interface Counters
Using CDP to Troubleshoot
The traceroute Command
The show controllers Command
debug Commands
Using Timestamps
Generic Host Networking Commands
The ip http server Command
Configuring a Device to Accept a Remote Telnet Connection
Using Telnet to Remotely Connect to Other Devices
Verifying Telnet
Chapter 24 Backing Up and Restoring Cisco IOS Software and Configurations
Boot System Commands
The Cisco IOS File System
Viewing the Cisco IOS File System
Commonly Used URL Prefixes for Cisco Network Devices
Deciphering IOS Image Filenames
Backing Up Configurations to a TFTP Server
Restoring Configurations from a TFTP Server
Backing Up the Cisco IOS Software to a TFTP Server
Restoring/Upgrading the Cisco IOS Software from a TFTP Server
Restoring the Cisco IOS Software from ROM Monitor Mode Using Xmodem
Restoring the Cisco IOS Software Using the ROM Monitor Environmental Variables and tftpdnld Command
Secure Copy
Configuring a Secure Copy Server
Verifying and Troubleshooting Secure Copy
Configuration Example: Using Secure Copy
Part VII: Wireless Technologies
Chapter 25 Configuring Secure Wireless Access
Connecting to a Cisco Wireless LAN Controller (WLC)
Configuring a WLAN Using WPA2 PSK
Appendix A How to Count in Decimal, Binary, and Hexadecimal
How to Count in Decimal
How to Count in Binary
How to Count in Hexadecimal
Representing Decimal, Binary, and Hexadecimal Numbers
Appendix B How to Convert Between Number Systems
How to Convert from Decimal to Binary
How to Convert from Binary to Decimal
How to Convert from Decimal IP Addresses to Binary and from Binary IP Addresses to Decimal
A Bit of Perspective
How to Convert from Hexadecimal to Binary
How to Convert from Binary to Hexadecimal
How to Convert from Decimal to Hexadecimal
How to Convert from Hexadecimal to Decimal
Appendix C Binary/Hex/Decimal Conversion Chart
Appendix D Password Recovery Procedures and the Configuration Register
The Configuration Register
A Visual Representation of the Configuration Register
What the Bits Mean
The Boot Field
Console Terminal Baud Rate Settings
Changing the Console Line Speed: CLI
Changing the Console Line Speed: ROM Monitor Mode
Password-Recovery Procedures for Cisco Routers
Password Recovery for Catalyst 9000/9200/9300 Series Switches
Password Recovery for Standalone Switches
Password Recovery for Stackwise Deployments
Appendix E Create Your Own Journal Here

9780138208684 TOC 1/12/2026

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