Section 8

Question 1

Router

Answer 1

a box that connects network IDs
-Only care about destinations
Interconnects network IDs
Routing table: 4 columns, all 0s in the Gateway mean you’re directly connected to that network
Default route- If it doesn’t know where to send something always send it to the default route
Upstream router
Gateway Routers
Metric- relative value that gives your router an idea if it has choice to choose something

Question 2

Port Number

Answer 2

Destination Port number and Source Port number. Your computer generates the ephemeral port number
Every TCP packet has two port numbers
Well known port numbers run from 0 to 1023

Question 3

Network Address Translation (NAT)-

Answer 3

Static NAT (SNAT)- assign 1 IP address that all incoming IP addresses go to
Dynamic NAT (DNAT)- router is given 2 IP addresses so if one of the devices on the network want to use the internet they will be given an IP Address. Problem is you have a fixed number of IP addresses
Port Address Translation- translate internal IP addresses to an Internet address and tracks the packets
SOHO routers ship with NAT enabled
NAT on a SOHO router can be disabled from the routers configuration page
Some older routers call this setting gateway/router mode

Question 4

Port Forwarding

Answer 4

allows external devices to have internal communication through a router

Question 5

Port Range forwarding

Answer 5

setting a specific range for the port numbers

Question 6

Port triggering

Answer 6

FTP: port 20, 21. Will open an alternative assigned port when the initial port is contacted

Question 7

SOHO DMZ

Answer 7

Remove the filter from the router to allow anything to come to your computer from the internet

Question 8

Home routers

Answer 8

Default IP address- along with Default username and password. 192.168.1 or 192.168.0 are most common

Question 9

Possible Network + question: can you configure your router’s web interface remotely.

Answer 9

Answer: yes

Question 10

Almost all home routers are DHCP servers

Question 11

Enterprise router

Answer 11

designed for more robust and enterprise situations. 100x bandwidth.

Question 12

SOHO router

Answer 12

will be a WAP, Switch, and Router. Will have a customizable firewall

Question 13

10S interface

Answer 13

Cisco interface

Question 14

Routing tables

Answer 14

if 0s in the beginning you don’t care. Send out on the gateway through my network card. Unless you see the loopback address

Question 15

Multicast

Answer 15

is a class D IP address. Allows a computer to take on a second IP address that starts with a 224

Question 16

Private “intranet” route

Answer 16

allow computers on a different router to connect to that computer

Question 17

Static route

Answer 17

is a fixed route that is manually configured and persistent

Question 18

Dynamic routing

Answer 18

putting smarts inside a router so they can rewrite their routing tables on the fly to adjust for changes and bring everything to a convergence. Convergence is where all router tables reflect all routes.

Question 19

Hop count

Answer 19

of routers it took to get to a particular network ID

Question 20

Maximum transmission unit (MTU)

Answer 20

in a particular frame how much data can you haul
Bandwidth, cost, and Latency(ping)

Question 21

Distance vector and link state

Answer 21

distance vector sends its entire routing table to its neighbors. Big issue, distance vectors use hop count. Link state sends out pings to neighbors and detects differences. Link state uses advertising.

Question 22

Dynamic routing protocols

Answer 22

are either IGP or EGP

Question 23

Border Gateway Protocol (BGP)

Answer 23

only EGP there is. Use ASN (autonomous system number)

Question 24

RIP- routing information protocol

Answer 24

Is a distance vector protocol that uses hop count to determine routes. Maximum hop count of 15
RIP1 used only classful networks

Question 25

Open Shortest Path First (OSPF)

Answer 25

is a link state protocol. Uses Area IDs. converges quickly

Question 26

BGP

Answer 26

hybrid protocol, breaks the internet into AS. Primary protocol for the interest