Section 8 Flashcards
Router
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
Port Number
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
Network Address Translation (NAT)-
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
Port Forwarding
allows external devices to have internal communication through a router
Port Range forwarding
setting a specific range for the port numbers
Port triggering
FTP: port 20, 21. Will open an alternative assigned port when the initial port is contacted
SOHO DMZ
Remove the filter from the router to allow anything to come to your computer from the internet
Home routers
Default IP address- along with Default username and password. 192.168.1 or 192.168.0 are most common
Possible Network + question: can you configure your router’s web interface remotely.
Answer: yes
Almost all home routers are DHCP servers
Enterprise router
designed for more robust and enterprise situations. 100x bandwidth.
SOHO router
will be a WAP, Switch, and Router. Will have a customizable firewall
10S interface
Cisco interface
Routing tables
if 0s in the beginning you don’t care. Send out on the gateway through my network card. Unless you see the loopback address
Multicast
is a class D IP address. Allows a computer to take on a second IP address that starts with a 224
Private “intranet” route
allow computers on a different router to connect to that computer
Static route
is a fixed route that is manually configured and persistent
Dynamic routing
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.
Hop count
of routers it took to get to a particular network ID
Maximum transmission unit (MTU)
in a particular frame how much data can you haul
Bandwidth, cost, and Latency(ping)
Distance vector and link state
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.
Dynamic routing protocols
are either IGP or EGP
Border Gateway Protocol (BGP)
only EGP there is. Use ASN (autonomous system number)
RIP- routing information protocol
Is a distance vector protocol that uses hop count to determine routes. Maximum hop count of 15
RIP1 used only classful networks
Open Shortest Path First (OSPF)
is a link state protocol. Uses Area IDs. converges quickly
BGP
hybrid protocol, breaks the internet into AS. Primary protocol for the interest
