Objective 1 Network Architecture Flashcards
Router
Any piece of hardware or software that forwards packets based on their destination IP address. Routers work at the Network layer of the OSI and at the Internet layer of the TCP/IP model
Switch
looks like a hub because all nodes plug into it, but they take advantage of MAC addresses, effectively creating point-to-point connections between two conversing computers.
Multilayer switch
A Layer 3 switch forwards traffic based on IP and is a router that does what a traditional router does in software… in hardware and is by definition a multilayer switch
Firewall
Devices or software that protect an internal network from unauthorized access by acting as a filter.
IDS
Intrusion Detection System - an application that inspects packets, looking for active intrusions. an IDS functions inside the network.
IPS
Intrusion Protection System - sits directly in the flow of network traffic. An IPS can stop an attack while it is happening, network bandwidth and latency take a hit, and if IPS goes down, the link might go down too.
Access Point (Wireless/wired)
A device designed to interconnect wireless network notes with wired networks. A basic WAP operates like a hub and works at OSI layer 1.
Content Filter
AKA Content Switch - works at layer 7 of the OSI. They work with web servers and are able to read the incoming HTTP and HTTPS requests. This allows advanced actions like handling SSL certificates and cookies removing the workload from the web servers.
Load balander
Making a bunch of servers look like a single server, creating a server cluster.
Hub
A central box in early days of networking. When it receives a frame, it makes an exact copy of that frame sending a copy of the original frame to every other system on the network.
Analog modem
Old-style analog-to-digital devices. Modulator converts digital to analog. A demodulator converts analog to digital. Device that does both is a modem.
Packet Shaper
A traffic shaping devices that controls the flow based on packet rules.
VPN Concentrator
A VPN-capable router. Layer 2 Tunneling Protocol (L2TP) and PPTP and Layer 2 Forwarding (L2F) and added support to run on almost any type of connection possible.
VPN
Virtual Private Network encrypted tunnels between a computer or a remote network and a private network through the internet.
site to site/host to site/host to host
site-to-site - enables two separate LANS to function as a single network, sharing files and services as if in the same building.
Host-to-site - connect a single faraway PC to cisco VPN
host-to-host - a specific single connection between two machines using VPN software or hardware.
Protocols
An agreement that governs the procedure used to exchange information between cooperating entities; usually includes how much information is to be sent, how often it is sent, how to recover from transmission errors, and who is to receive the information.
IPSec
Internet Protocol Security - an authentication and encryption protocol suite that works at the internet/network layer and should become the dominant authentication and encryption protocol suite as IPv6 continues to roll out.
GRE
Generic Routing Encapsulation - used to make point-to-point tunnel connection that carries all sorts of traffic over Layer 3, including multicast and IPv6 traffic.
SSL VPN
Secure Socket layer VPN. Does not require any special client software. Clients connect to the VPN server using a standard Web browser with the traffic secured using SSL.
PTP/PPTP
Point-to-Point Tunneling Protocol - an advanced version of PPP that queries for an IP address and creates a secure tunnel through the internet back to the Private LAN.
TACACS/RADIUS
Terminal Access Controller Access Control System was developed by Cisco to support AAA in a network with many routers and switches. Uses TCP port 49 by default, separates authorization, authentication and accounting into different parts. Uses PAP, CHAP and MD5 hashes as well as Kerberos.
Remote Authentication Dial-In User Service is the better know AAA standard and was created to support ISPs with thousands of modems in hundreds of computers to connect to a single central database.
RAS
A server running the Routing and Remote Access Service dedicated to handling users who are not directly connected to a LAN but who need to access file and print services on the LAN from a remote location.
Web services
Applications and processes that ban be accessed over a network, rather than being accessed locally on the client machine. Web services include things such as web-based e-mail,k network-shareable documents, spreadsheets, and databases, and many other types of cloud-based applications.
Unified voice services
Complete, self-contained internet services that rely on nothing more than software installed on computers and the computers’ microphone/speakers to provide voice telecommunication over the internet. All of the interconnections to PSTN are handled in the cloud.
Network controllers
a program that can dictate how both physical and virtual network components move traffic through the network.
DHCP
Dynamic Host Configuration Protocol - automatically assigns an IP address whenever a computer connects to the network.
Static vs dynamic IP addressing
typing all the information in (static addressing) or by having a server program running on a system that automatically passes out all IP information as they boot up (dynamic addressing)
Reservations
Setting DHCP sever to reserve addresses for specific machines
Scopes
A range of IP addresses configured on DHCP server to pass out as needed
Leases
A fixed amount of time, generally 5-8 days, that a DHCP server assigns IP information to a machine. Near the end of the lease time, the server looks at the MAC address information and unless another computer has taken the lases, give the DHCP client the same IP information.
Options (DNS servers, suffixes)
A special option to the DHCP server, called the DNS suffix, it helps the clients access network resources more efficiently
IP helper/DHCP relay
DNS servers that redirect your browser to advertising when you type in an incorrect URL
DNS
Domain Name System - a name resolution protocol that supports name resolution on time in-house networks as well as the entire internet.
DNS Servers
Top-level domain servers (com, org, etc) that delegate to thousands of second-level DNS servers (totalsem.com, whitehouse.gov).
DNS Records (A, MX, AAAA, CNAME, PTR)
A records are the IPv4 addresses and names of all the systems on the totalhome domain.
MX Records are used exclusively by SMTP server to determine where to send mail.
(CNAME) A Canonical Name record acts like an alias
AAAA records are for IPv6 IP addressing
PTR pointer record created for a reverse lookup zone
Dynamic DNS
(DDNS) Enables DNS servers to get automatic updates of IP addresses of computers in their forward lookup zones, mainly by talking to the local DHCP server.
Proxy, Reverse Proxy
Proxy Server sits between clients and external servers, pocketing the requests from the clients for server resources and making those requests itself. The client computes never touch the outside servers and thus stay protected from any unwanted activity.
Reverse Proxy acts on behalf of its servers. Clients contact the revers proxy server, which gathers information from its associated servers and hands that information to the clients.
NAT
Network Address Translation - hides the IP addresses of computers on the LAN but still enable those computers to communicate with the broader internet.
PAT
most common form of NAT that handles one-to many connections - uses port number to map traffic from specific machine in the network.
SNAT
Static NAT maps a single routable IP address to a single machine, enabling you to access that machine from outside the network.
DNAT
Dynamic NAT - many computers can share a pool of routable IP addresses that number fewer than the computers.
Port Forwarding
you can designate a specific local address for various network services.