CCNA Chapter 1

Describe cell-switched services.

"Cell-switched services provide the same features that dedicated circuits offer, but their advantage is that a single device can connect to multiple devices on the same interface. "

What is a good encryption solution to guard network login information?

"Encrypt information between two network components so that login credentials cannot be viewed; for example, it is better to use SSH instead of telnet for remote access because SSH encrypts the session traffic."

Name 9 common network components.

"Hubs, bridges, switches, routers, firewalls, wireless access points, modems, NT1s (Network Terminator Type 1 is an ISDN network termination device), and channel service units/data service units (CSU/DSUs)."

Name 4 maintenance threats.

"Not having backup parts or components for critical network components; not labeling components and their cabling correctly, causing problems when performing maintenance in and around network components; and not following electrostatic discharge procedures before handling network components."

Describe 3 types of network attacks and their solutions, including recommended devices.

1) Reconnaissance - Mitigation: ACL's Devices: IPS, IDS, routers 2) Access - Mitigation: Authentication, port security, virtual LANs (VLANs), ACLs, virtual private networks (VPNs) Devices: Switches, routers, firewalls, IPS, IDS 3) DoS - Mitigation: ACL's Devices: IPS, IDS, firewalls, routers.

Name and describe the 4 types of networking locations.

1) Small Office/Home Office (SOHO) - Home or small office with a handful of people. 2) Branch Office - Users are connected in a small area that is geographically separated from the corporate office. 3) Mobile Users - Can connect to the network from any location, LAN, or Wan. 4) Corporate or Central Office - Most of the network users and resources are located in one location.

What is the difference between an UPS and a surge protector?

A UPS protects against a complete loss of power, while a surge protector protects equipment from power spikes and surges.

Describe a star topology.

A central device has many point-to-point connections to other components. Star topologies are used in environments where many different devices need to be connected, with a hub or switch at the center of the star.

What is a network?

A network is all of the components involved in connecting computers and applications across small and large distances to increase productivity and give easy access to information.

What is the most common type of access attack?

A password attack when an adversary tries to guess a valid password for an existing account.

Describe a dedicated circuit.

A permanent connection between two sites in which the bandwidth is dedicated to that company's use. Common when services such as voice, video, and data, must traverse the connection.

Give 2 examples of cell-switched services.

ATM and SMDS.

What are 2 ways to mitigate scanning and packet sniffing attacks?

Access control mechanisms such as firewalls, and IDS/IPS.

Describe a bus topology.

All components are connected to and share a single wire using special types of connectors or transceivers.

Describe a close-in network attack.

An adversary attempts to get physically close to network components, data, and systems in order to learn more about a network or to cause damage.

Describe a distributed network attack.

An adversary introduces code, such as a Trojan horse or back-door program, to a "trusted" component or software that will later be distributed to many other companies and users.

What is a network Adversary, and give 7 examples.

An adversary is a person or persons interested in attacking your network. Common adversaries include disgruntled employees, unskilled and skilled hackers, criminals, other countries, terrorists, and competing companies.

Describe a passive network attack.

An adversary monitors monitors unencrypted traffic and looks for clear-text passwords and sensitive information that can be used in other types of attacks.

Describe an active network attack.

An adversary tries to bypass or break into secured systems using stealth, viruses, worms, or Trojan horses, or by exploiting a discovered security vulnerability.

In a network, what is a "network-aware" application?

An application that allows you to access and use resources that are not located on your local computer.

Describe an insider network attack.

An inside adversary attempts to eavesdrop, copy, or cause damage to information, often using a sniffing tool such as Wireshark.

Give 2 examples of circuit-switched services.

Analog dial-up and ISDN.

Name 9 services available via a WAN.

Analog dialup, asynchronous transfer mode (ATM), dedicated circuits, cable, digital subscriber line (DSL), Frame Relay, Integrated Services Digital Network (ISDN), Switched Multi-megabit Data Services (SMDS), and X.25

How is network Availability measured?

As an "uptime" annual percentage that is calculated by taking the number of minutes the network is available and dividing it by the number of minutes in a year, which is 525,600.

How is network Reliability measured?

As the Mean time between Failures - or MTBF - which is a measurement used to indicate the likelihood of a component failing.

What are 7 networking devices that are used in WAN connections?

Cable and DSL modems, carrier switches, CSU/DSU's, firewalls, modems, NT1's, and routers.

Where are WAN's leased from?

Carrier networks, such as telephone companies and Internet service providers.

What are the 4 basic type of WAN connections or circuits?

Circuit-switched, cell-switched, packet-switched, and dedicated connections.

What 3 component categories do you need to build a network?

Computers, networking, and media.

Name 6 types of media used in a LAN.

Copper and fiber cabling. Ethernet, Fast Ethernet (FE), Gigabit Ethernet (GE), Token Ring, and fiber distributed data interface (FDDI).

What 7 characteristics should be considered when creating or maintaining a network?

Cost, security, speed, topology, scalability, reliability, and availability.

What are the 2 main disadvantages of DSL?

Coverage is limited to about 18,000 feet, and it is not available in all areas.

What are 4 characteristics of DSL?

DSL provides speeds up to a few megabits per second (Mbps), it costs much less than a typical WAN circuit from the carrier, it supports both voice and video, and doesn't require a dial-up connection.

What resources are commonly shared across a network?

Data and applications, printers, network storage components, and backup storage components.

Describe a ring topology.

Device one connects to device two, device two connects to device three, and so on to the last device, which connects back to the first device. Ring topologies can be implemented with a single ring or a dual ring.

What are 3 common networking applications?

E-mail, FTP, and web applications.

What is the de facto standard for LAN-based networks?

Ethernet.

Describe partial meshing.

Every network component is NOT connected to every other component.

Describe full meshing.

Every network component is connected to every other network component.

Give an example of a media technology that uses dual rings to connect computer components.

Fiber distributed data interface (FDDI).

What are 2 types of DoS attacks?

Flood attacks, such as Internet Control Message Protocol (ICMP) and TCP SYN flooding, as well as buffer overrun attacks

Describe a possible DoS attack scenario.

Flooding millions of packets or injecting code into an application or overrunning the buffer(s) of an application, causing it to crash.

Give 2 examples of packet-switched services.

Frame Relay and X.25.

What are 4 types of physical installation threats?

Hardware, electrical, environmental, and maintenance.

What does a network topology define?

How network components are connected.

What does a physical topology describe?

How network components are physically cabled together.

What does a logical topology describe?

How network components communicate across the physical topology.

Describe 3 logical security controls.

Idle timeout on logins, passwords, and authentication methods.

What is the main disadvantage of a star topology, and how can it be overcome?

If the center of the star fails, no devices can communicate. Overcome by using an extended star topology that is multiple interconnected star topologies.

Most threats to a network are what kind?

Internal, therefore developing a security plan to deal with physical threats is important.

Name 2 types of electrical threats.

Irregular fluctuations in voltage, such as brownouts and voltage spikes, and complete loss of power.

Describe the mesh topology in a network environment.

It describes how network components are connected together, and can be either full or partial.

How does rate limiting protect a network?

It ensures that a system doesn't become overwhelmed by a flood attack.

Describe a point-to-point topology.

It has a single connection between two components, and two components can directly communicate without interference from other components.

Describe a circuit-switched service.

It provides a temporary connection across a phone circuit and are typically used for backup of primary circuits and for temporary boosts of bandwidth.

What does a token card do?

It uses a one-time password (OTP) that generates a different, dynamic password each time a user logs into a system.

Name 2 major disadvantages of Cable access.

It uses a shared logical bus topology, so if there are more customers, each customers gets less bandwidth. It is also more susceptible to security risks.

What are 2 characteristics of Cable access?

It uses coaxial copper and fiber connections, and it supports higher rates than DSL.

Name 4 ways to mitigate network threats.

Maintain parts on hand, clearly label and run cables, perform electrostatic discharge procedures, and have idle timeouts on any network component that has a login.

What specific requirements are needed for large data transfers for things such as Voice over IP (VOIP) and video Quality of Service (QoS)?

Minimal delay and latency.

What are 2 maintenance points about methods to mitigate electrical threats?

Mitigation systems should be monitored and periodically tested.

What is the formula that is used to determine the number of links needed to fully mesh a WAN?

N x (N-1) divided by 2, where N is the number of locations.

How do you mitigate a social engineering attack?

Network users should go through proper training about the kinds of information that they can or can't share with other people.

Should carpeting or similar materials should exist in a room with critical network components?

No, since they can create static electricity that can damage the components.

Name 9 network devices commonly found in a LAN.

PCs, file servers, hubs, bridges, switches, routers, multilayer switches, voice gateways, and firewalls.

Describe packet-switched services.

Packet-switched services are similar to cell-switched services, except where cell-switched services switch fixed-length packets called cells, packet-switched services switch variable-length packets. This feature makes them better suited for data services.

Name the 5 classes of network attack.

Passive, active, insider, distributed, and close-in.

Name 2 good network password practices.

Passwords should be at least 10 characters long, and users shouldn't be allowed to use the same password on different network components.

What are hardware threats?

Physical damage to network components.

What are 4 categories of common network threats?

Physical installations, reconnaissance attacks, access attacks, and denial of service (DoS) attacks

What are the 2 types of security controls?

Physical or logical.

Describe the physical and logical topologies of Ethernet media.

Physical: bus, star, or point to point Logical: bus

Describe the physical and logical topologies of FDDI media.

Physical: ring Logical: :ring

Describe the physical and logical topologies of Token Ring media.

Physical: star Logical: ring

How do you reduce the likelihood of hardware threats?

Please critical network components in locked rooms that are not accessible by windows, air vents, dropped-down ceilings, or raised flooring.

What do Protocols do?

Protocols are used to implement applications.

Which network characteristic is concerned about MTBF?

Reliability.

Describe 4 physical security controls.

Sign in and out logs, locks, guards, and doors.

Name 5 common network protocols.

Simple Mail Transfer Protocol (SMTP), Internet Message Access Protocol version 4 (IMAP4), Post Office Protocol 3 (POP3), File Transfer Protocol (FTP), and Hypertext Transfer Protocol (HTTP)

Why should a monitoring system be used to protect against environmental threats?

So that an administrator can take immediate action if anomalies occur in temperature or humidity.

What are 3 tools that adversaries use in reconnaissance attacks?

Social engineering, scanning tools, and packet sniffers.

What are network security appliances?

Specialized network components that typically provide many security functions.

What are 2 downsides to using cell-switched services?

They are not available at all locations, and they are difficult to set up and troubleshoot,

How does magnetic interference affect network components?

They can cause damage to network components such as disk drives.

What are Wide Area Networks (WAN's) used for?

To connect LAN's together, even when they are separated by a large distance.

What are Local area networks (LANs) used for?

To connect networking devices that are in a very close geographic area.

What is the purpose of network filters, such as Access Control Lists?

To restrict access to network components and their information, such as only allowing accounting employees access to the accounting server.

What is an example of a point-to-point topology?

Two routers connected across a dedicated WAN circuit.

What are 3 ways to mitigate electrical threats?

Use uninterruptible power supplies, backup generator systems, or redundant power supplies.

What are 2 types of password attacks?

Using a password cracking program that will use a dictionary to guess common passwords or use a brute-force approach by guessing every combination of numbers, letters, and special characters.

How can DoS attacks be mitigated?

Using access control mechanisms such as packet filtering to control access to a system.

How to you mitigate Trojan Horse attacks?

Using an IDP/IPS and anti-spyware software.

What are 4 environmental threats?

Very low or high temperatures, moisture, electrostatic, and magnetic interference.

How should secure network rooms be monitored?

Via electronic access control and video monitoring.

What type of mesh topology does a WAN use, and why?

WAN's typically use a partial mesh topology in order to reduce the cost of connecting components and locations.

What does a security policy define, and what is derived from it?

What people can and can't do with network components, and a security solution is derived from the security policy.

What is a Denial of Service (DoS) attack?

When an adversary reduces the level of operation or service, preventing access to, or completely crashing a network component or service.

What is a reconnaissance attack?

When an adversary tries to learn information about a network.

When are dual ring topologies used, and what is the benefit?

When redundancy is needed, and the benefit is that in a dual-ring topology, the ring can loop back on itself.

What is an access attack?

When someone tries to gain unauthorized access to a component, to unauthorized information on a component, or to increase their privileges on a network component.