Intranet, Password Encryption and Configuration

Intranet

• A private network of interconnected LANs and WANs owned by an organization
• Designed to be accessible only to the organization's employees or members
• Allows them to share information, communicate, and collaborate efficiently within a controlled environment

Service Password Encryption

• The command encrypts all configured passwords in the configuration file
• Prevents passwords from appearing in plain text

Password Protection

• Passwords can restrict access to parts of the Cisco IOS
• Secure the Console interface for direct, local access.
• Secure the Privileged EXEC mode to prevent unauthorized access to advanced commands.
• Secure the VTY interface for remote access via Telnet or SSH.

copy running-config startup-config Command

• Replaces the startup configuration with the current configuration
• This saved configuration then loads automatically when the device restarts

Switch Virtual Interface (SVI)

• A Layer 2 switch includes an SVI to allow remote management of the device over the network.

User EXEC Mode Access

• Access obtained through the console port requires the password set under the line console 0 command.
• Privileged EXEC mode access is granted by the enable and enable secret passwords.

SSH vs. Telnet

• SSH encrypts messages and uses user authentication for secure remote sessions.
• Telnet sends messages in plaintext and is considered insecure.
• SSH is the suggested protocol for network access due to its security features.

Discarding Router Configuration Changes

• The reload command discards unsaved changes in the current router configuration file.
• The command allows working with the file in NVRAM.

service password-encryption Command

• Encrypts all plain-text passwords (console, VTY, auxiliary) in the configuration file
• Makes the passwords appear as encrypted characters

Subnet Mask Definition

• It determines which part of an IPv4 address refers to the network, and which part refers to the host.
• Essential for routing and proper communication.

Layer 2 Switch IP Address

• Required only for remote management using tools like Telnet or SSH
• Not needed for forwarding packets.

Loopback Test Information

• Tests if a device can communicate with itself using its own network software
• Does not check the network, cables, or connections to other devices

Remote Routes

• Specify a next hop address to reach a destination network not directly connected to the router
• Typically come from other routers

NAT in IPv6

• Not needed because IPv6 provides enough public IP addresses for every device
• IPv6 eliminates the need to conserve address space

Default Gateway Address for a Switch

• Used to forward packets originating from a switch to remote networks
• Routes packets to the relevant network or device when the switch cannot send a packet locally.

Probable Cause of Network Access Issues

• An invalid default gateway address prevents a computer from accessing devices on other networks
• The default gateway is needed for routing packets to remote networks.

transport input ssh Command

• When entered on the switch VTY lines, communication becomes encrypted between the switch and remote users

Secure Access to a Router via Console Interface

• Use the line console 0 command to enter console line configuration mode
• Set a password with the password cisco command
• Apply the login command to require password authentication.

IPv4 Multicast Address Range

• Reserved Class D address range between 224.0.0.0 to 239.255.255.255

Broadcast Address of Network 172.16.16.0/22

• Network portion consists of 22 bits, and the host portion consists of 10 bits.
• The subnet mask is thus 255.255.252.0.
• Valid host addresses range between 172.16.16.1 and 172.16.19.254.
• The broadcast address is 172.16.19.255.

Unroutable IP Address

• The IP address 192.168.25.10 is an IPv4 private address
• Because it is private, it will not be routed over the Internet

IPv6 Link-Local Address

• Used for communication within the same network segment.
• Denoted by the prefix FE80::/10.
• Distinct from global unicast, multicast, and loopback addresses.

IPv6 Address Compression

• The longest consecutive group of zero segments can be replaced with a double colon :: (only once in an address)
• Leading zeros in each segment can be eliminated

IPv6 Multicast Packet Target

• Destination address of FF02::1 targets all IPv6-enabled devices on the local link.

IPv6 Prefix Determination

• Determined by the first 64 bits of an address
• For the address 2001:DB8:BC15:A:12AB::1/64, the prefix is 2001:DB8:BC15:A

EUI-64 Process

• Uses the MAC address to make an IPv6 interface ID

IPv6 Anycast Address

• A unicast address assigned to multiple hosts.
• Data is sent to the closest host based on routing, unlike multicast which sends data to multiple devices.

ICMP Messages

• Used to provide feedback on the status of IP packet transmissions
• Helps in reporting errors and to check connectivity between devices

192.168.1.64/26 Subnet

• Has usable host addresses from192.168.1.65 to 192.168.1.126
• 192.168.1.96 falls within this range and is a valid host address

Windows PC APIP Indication

• Indicates the PC is unable to reach a DHCP server
• PC automatically assigns itself a link-local address

Determining Router Interface for Remote Networks

• The show ip route command displays the IP routing table of the router
• Shows known local and remote networks and the interfaces the router uses to reach them.

Using the tracert Utility

• Used to identify the path a packet takes from source to destination.
• Determines where packets are dropped or delayed for troubleshooting.

SSH Configuration on a Router

• Configure the correct IP domain name
• Create a valid local username and password database
• Generate the asymmetric RSA keys

Port Security Violation

• Happens when a port enters the err-disabled state as when an unauthorized device with a different MAC address attempts to connect
• Protects the network from potential security threats

EtherChannel Technology

• Provides increased bandwidth by bundling existing FastEthernet or Gigabit Ethernet interfaces into a single channel
• Provides redundancy in case one or more links in the channel fail

EtherChannel Mode

• "On" mode bundles the links unconditionally.
• No negotiation protocol is used in this mode

Enable Sticky MAC Addressing

• Enables the switch to automatically add a printer's MAC address allowing it to communicate with other devices

Port Security Violation Mode Configuration

• Setting the port security violation mode to shutdown causes the port to enter an err-disable state

option D Correct Response Explanation

• Creates a backup route with a higher administrative distance
• Creates a lower chance of selecting the backup route.

Ethernet Switch Unused Ports

• Can be configured via admin shutdown to improve the security of a network

IPv6 Static Address Assignment

• To connect two ends and set and IPv6 address to the interface.

Trunking Protocol

• IEEE 802.1q is the industrial standard used for configuration of trunking on both sides of third party devices

Route Advertisement Prevention

• Router cannot have the same broadcast IP listed and as a result it drops the command and prevents route advertisement.

Static Route Recommendation

• Should involve a lower amount of hops

Default Route Advertisement Recommendation

• Requires advertising by 0.0.0.0

Network Operation

• Without access to the internet requires a private address