Routing Flashcards
What level do routers work at?
Layer 3
On a router, what does a console port do?
Used to plug in laptops and directly interact with the router for maintenance
Switches that can also route are called _______
Multi-layer switches MLS
What’s the first thing a router does when it gets a frame?
Strips away the MAC data to replace it
What 5 things will you commonly see on a routing table?
Destination - The IP of the connected node
Gateway - The gateway of the router. Takes any packets not able to be locally sourced.
Genmask - Another name for subnet
Type - Whether the call is to the WAN port or on LAN ports
Metric - Priority
On a routing table, what is a flag?
A letter used to indicate certain properties of a connection.
Ex: C - Connected
H - Destination is a host
True or false: Routers will send the packet to the first matching address on the routing table they find
False. They will scan the whole routing table before sending
What does a 0.0.0.0 address mean on a routing table
The IP address doesn’t matter
What would be the result of
DEST GATEWAY GENMASK TYPE
192.168.0.3 * 255.255.255.0 LAN
ARP out to the LAN for the MAC address, then send the packet to that recipient.
What would be the result of
DEST GATEWAY GENMASK TYPE
192.168.0.0 * 255.255.255.0 WAN
ARP out to WAN port
What is the win command for seeing your routing table
route print
What is dynamic routing protocol
Routers sharing information to keep their routing tables optimal
What is port address translation?
When a NAT device maps internal addresses and ports to routable ones, allowing private IPs to talk to external networks.
More info:
Priv IP computer sends a packet for an external network on 192.168.0.5:2000 > As this isn’t a routable IP, the NAT device substitutes the Priv IP and port for its own Routable ones. It then remembers the port it has used so it knows how to translate it back when the packet returns from the web.
What is port forwarding?
Enabling external, unsolicited connections via specific ports. It forwards the information to a specific computer listening on that port.
What is Pooled Nat?
Dynamic NAT. Using a pool of routable IP addresses amongst computers. Leasing them out as needed temporarily.
What’s the difference between PAT and Port forwarding?
PAT translates IP and ports for outgoing connecitons
Port forwarding forwards information on incoming connections into the network via ports.
What is SNAT?
Static NAT maps a single, routable address to a specified machine. This enables access externally to the PC or server.
What is Distance Vector
Something used by networking protocols that prioritize the hop count between source and destination to dictate the metrics of routing tables.
True or false x2
Distance Vector updates at 30s intervals (aside from RIPv2 which is 90)
Link state deletes all alternate paths to a single point from its routing table apart from the most efficient method
Both true
What is convergance/steady state
When routers have finished exchanging routing information and have optimal paths.
How many routers is it suggested you use with RIP, the distance vector protocol?
Less than 10 due to the 30s interval of information regarding routing tables can overload your network
What is an AS?
Autonomous Systems are owned by big name networks in each country and use a unified policy to communicate.