Module 1 Flashcards
What are the five steps in the switch boot sequence?
Load POST (Power-On Self-Test) from ROM.
Load boot loader software from ROM.
Boot loader initializes CPU registers.
Boot loader initializes the flash file system.
Boot loader loads IOS and hands control to it.
How is the BOOT environment variable set?
Use the boot system command in global configuration mode. Example:
boot system flash:<path-to-IOS-file>.</path-to-IOS-file>
What do the following switch LEDs indicate?
SYST
RPS
STAT
DUPLX
SPEED
PoE
SYST: System power and functionality.
RPS: Redundant Power Supply status.
STAT: Port status (default mode).
DUPLX: Port duplex mode.
SPEED: Port speed mode.
PoE: Power over Ethernet status.
How do you access the boot loader to recover from a system crash?
Connect via console cable.
Power cycle the switch.
Press and hold the Mode button until the SYST LED turns amber, then green.
Use boot loader commands to recover (e.g., dir to view files).
What is required to manage a switch remotely?
An IP address and subnet mask on the switch.
A default gateway if managing from a different network.
How do you configure an SVI for management?
Enter global config mode: configure terminal.
Enter interface config mode: interface vlan <vlan-id>.
Assign IP address: ip address <ip> <subnet-mask>.
Enable the interface: no shutdown.
Save config: copy running-config startup-config.</subnet-mask></ip></vlan-id>
What is the difference between full-duplex and half-duplex communication?
Full-duplex: Simultaneous two-way communication (no collisions).
Half-duplex: One-way communication at a time (collisions possible).
What is Auto-MDIX, and why is it useful?
Auto-MDIX automatically detects and configures cable type (straight-through or crossover).
It eliminates the need for specific cable types when connecting devices.
Why is SSH preferred over Telnet?
Telnet: Unencrypted, insecure (uses plaintext).
SSH: Encrypted, secure (uses TCP port 22).
What are the steps to configure SSH on a switch?
Verify SSH support: show ip ssh.
Configure IP domain: ip domain-name <domain>.
Generate RSA keys: crypto key generate rsa.
Configure user authentication: username <name> secret <password>.
Enable SSH on VTY lines: transport input ssh.
Enable SSH version 2: ip ssh version 2.</password></name></domain>
What are the initial steps to configure a router?
Name the device: hostname <name>.
Set passwords (enable secret, console, VTY).
Configure a banner: banner motd <message>.
Save configuration: copy running-config startup-config.</message></name>
What is required to activate a router interface?
Assign an IP address: ip address <ip> <subnet-mask>.
Enable the interface: no shutdown.
(Optional) Add a description: description <text>.</text></subnet-mask></ip>
What is a loopback interface, and why is it useful?
A logical interface internal to the router.
Always ‘up’ as long as the router is functioning.
Useful for testing, management, and simulating networks.
What commands verify interface status and configuration?
show ip interface brief / show ipv6 interface brief.
show running-config interface <interface-id>.
show ip route / show ipv6 route.</interface-id>
How do you filter the output of show commands?
Use the pipe (|) with:
* section: Show entire section.
* include: Include matching lines.
* exclude: Exclude matching lines.
* begin: Start output from matching line.
How do you use the command history feature?
Press Ctrl+P or Up Arrow to recall older commands.
Press Ctrl+N or Down Arrow to recall newer commands.
Use show history to view the command buffer.
Adjust buffer size: terminal history size <number>.</number>
What do the following errors indicate?
Input Errors
Runts
Giants
CRC Errors
Collisions
Input Errors: Total errors on received packets.
Runts: Packets smaller than minimum size.
Giants: Packets larger than maximum size.
CRC Errors: Checksum mismatches (cable/interface issues).
Collisions: Occur in half-duplex mode (not in full-duplex).
What is an IPv6 link-local address, and when is it used?
Automatically assigned to an interface when a global unicast address is configured.
Begins with FE80.
Used for communication on the local link (e.g., neighbor discovery).
What is a local host route, and what is its purpose?
A route with a /32 (IPv4) or /128 (IPv6) mask.
Used for the router’s own IP addresses.
Allows the router to process packets destined to its interfaces.
What steps should you take to troubleshoot connectivity issues?
Verify physical connections.
Check interface status (show interfaces).
Verify IP configuration (show ip interface brief).
Check for errors (e.g., CRC, collisions).
Test connectivity (e.g., ping, traceroute).
What happens when a switch powers on?
Runs a self-test (POST)
Loads a small program (boot loader)
Sets up the CPU and flash memory
Finds and loads the IOS (operating system)
How do you tell the switch which IOS to load?
Use: boot system flash:<path-to-IOS-file></path-to-IOS-file>
What do these switch lights mean?
SYST: System is on and working
STAT: Port status (green = good)
DUPLX: Port duplex mode (full/half)
SPEED: Port speed (10/100/1000 Mbps)
PoE: Power over Ethernet status
How do you fix a switch that won’t boot?
Connect to the console
Hold the Mode button while powering on
Use boot loader commands to fix or reinstall IOS
How do you manage a switch from another network?
Give the switch an IP address
Set a default gateway (router IP)
Use SSH or Telnet to connect
What is an SVI, and how do you set it up?
SVI: A virtual interface for managing the switch
Setup:
* interface vlan <vlan-id>
* ip address <ip> <subnet-mask>
* no shutdown</subnet-mask></ip></vlan-id>
What’s the difference between full-duplex and half-duplex?
Full-duplex: Send and receive data at the same time (no collisions)
Half-duplex: Send or receive, but not both (collisions can happen)
What does Auto-MDIX do?
Automatically detects if you need a straight-through or crossover cable and adjusts
Why is SSH better than Telnet?
Telnet: Sends data in plaintext (not secure)
SSH: Encrypts data (secure)
How do you enable SSH on a switch?
Set a hostname and IP domain
Generate RSA keys: crypto key generate rsa
Create a username/password
Enable SSH on VTY lines: transport input ssh
What are the first things to configure on a router?
Set a hostname: hostname <name>
Set passwords (enable secret, console, VTY)
Add a banner: banner motd <message>
Save config: copy running-config startup-config</message></name>
How do you make a router interface work?
Assign an IP address: ip address <ip> <subnet-mask>
Turn it on: no shutdown
(Optional) Add a description: description <text></text></subnet-mask></ip>
What is a loopback interface?
A virtual interface always ‘up’
Used for testing, management, or simulating networks
How do you check if an interface is working?
Use:
* show ip interface brief (IPv4)
* show ipv6 interface brief (IPv6)
Look for ‘up/up’ status
What is a link-local address?
Automatically assigned to IPv6 interfaces
Starts with FE80
Used for communication on the same network segment
What is a local host route?
A route for the router’s own IP address
Has a /32 (IPv4) or /128 (IPv6) mask
How do you filter command output?
Use | (pipe) with:
* include: Show only matching lines
* exclude: Hide matching lines
* begin: Start output from a specific line
How do you reuse old commands?
Press Up Arrow to see previous commands
Use show history to see the full list
Adjust history size: terminal history size <number></number>
What do these errors mean?
Runts: Packets too small
Giants: Packets too big
CRC: Checksum errors (bad cable/interface)
Collisions: Happen in half-duplex mode
How do you fix no connectivity?
Check cables and lights
Verify IP settings
Ping the default gateway
Look for errors in show interfaces
Why shouldn’t you use VLAN 1 for management?
It’s a security risk because it’s the default VLAN. Use a different VLAN for management
What is dual stack?
Running both IPv4 and IPv6 on the same device
What commands verify router settings?
show running-config: Current configuration
show ip route: IPv4 routing table
show ipv6 route: IPv6 routing table
What commands verify switch settings?
show interfaces: Interface status and errors
show mac address-table: MAC addresses learned by the switch
show vlan: VLAN configuration
What do Packet Tracer activities help with?
Practice configuring and verifying:
* Switch ports
* SSH
* Router interfaces
* IPv4 and IPv6 connectivity
