Chapter 8 - Routing Flashcards
Define Router
Any piece of hardware or software that forwards packets based on their destination IP address
How does a router determine the destination
By reading the IP addresses of the packets. Destination doesn’t matter
Define Gateway
The IP address for the next hop router; where the packet should go next.
What does the router do if there is more than one route
Picks the best one. the router with the lowest metric wins
In terms of routing, what does zero mean
Anything, like a wildcard
Why is this route important and translate the route into english: Destination: 0.0.0.0 Subnet Mask: 0.0.0.0 Gateway: 76.30.4.1 Interface: WAN
Any destination with any subnet mask forward it to 76.30.4.1 using my WAN port. This tells the router exactly what to do with every incoming packet unless another line says otherwise
Translate this route into english: Destination: 10.12.14.0 Subnet Mask: 255.255.255.0 Gateway: 0.0.0.0 Interface: LAN
Any packet for the 10.12.14.0/24 Network ID, don’t use a gateway, just ARP is on the LAN interface to get the MAC address and send to recipient
What is the Tier One Backbone
Where you’ll find the routers that make the main connections of the internet
Define Metric
a relative value that defines the ‘cost’ of using this route
What is a general statement to describe the internet
A Whole bunch of big powerful routers connected to lots of other big powerful routers
What is a loopback address
As long as it starts with 127 it will always go to 127.0.0.1
jWhat is the difference between a directed broadcast and a full broadcast
Directed broadcast goes only to the targeted subnet rather than the full broadcast domain
Define NAT
Network Address Translation hides the IP addresses of computers on a LAN but still enable those computers to communicate with the broader internet. The router replaces the source IP with its outside interface address
What is basic NAT
Translating the private or internal IP address to a global IP address on a one to one basis.
Define Port Address Translation (Pat)
Uses port numbers to map traffic from specific machines in the network
Define Static NAT
Maps a single routable IP address to a single machine
Define Dynamic NAT
Enables computers to share a pool of routable IP addresses that number fewer than the computer. Dynamic NAT is also called ‘Pooled NAT’
What is a ‘hop’ defined as
Each time a packet goes through a router