Networking Flashcards
What are the addressing schemes used for addressing network packets so they reach their destination?
- MAC (media access control) addresses, used by hardware.
- IPv4, IPv6 network addresses, used by software.
- Hostnames, used by people.
What do IP addresses identify?
A machines network interfaces?
What is a port?
A 16 bit number that supplements IP addresses to specify a particular communication channel.
What are the four IP address types?
- Unicast: Addresses that refer to a single network interface.
- Multicast: Addresses that simultaneously target a group of hosts.
- Broadcast: Addresses that include all hosts on a local subnet.
- Anycast: addresses that resolve to any one of a group of hosts.
How many bytes are IPv4 addresses?
4 Bytes.
Who sets the boundary between network and host portions of IPv4 addresses?
Administrator.
In what format are IPv4 addresses written?
Decimal numbers, 1 for each byte.
What decimal number is always part of the network portion in IPv4 addresses?
The left most number.
How many bytes are IPv6 addresses?
16 Bytes.
How many bytes are each the network and host portion in IPv6 addresses
8 Bytes each.
What was IPv6 originally created for?
To solve the problem of IP exhaustion.
What issues is IPv6 now being used to help solve?
Routing, mobility, and locality of reference.
Describe IPv6.
128 bits divided into 8 groups of 16 bits each. Separated by colons. Each 16 bit group is represented by hexadecimal digits.
What is IP spoofing?
When the IP address of the host from which a packet was sent has been changed/spoofed.
Who is the victim of IP spoofing?
The machine identified by the spoofed source. Error and return packets can disrupt their network connections.
What is the solution to IP spoofing
Block outgoing packets whose source address is not within your address space.
What is the security issue with IP forwarding?
Hosts that forward packets can be coerced into compromising security by making external packets appear to have come from inside the network.
What is the solution to issues with IP forwarding?
Turn off IP forwarding.
What are the two network interfaces each system minimally has?
Virtual loopback interface
One real network card or port.
What are the 4 steps in adding a new machine to a local network?
- Assign a unique IP address and hostname.
- Configure network interfaces and IP addresses.
- Set up a default route and perhaps fancier routing.
- Point to a DNS name server to allow access to the rest of the internet.
What is routing?
The process of directing a packet through the maze of networks that stand between its source and its destination.
Where is routing information stored?
In a routing table in the kernel.
What are the two distinct things the term “routing” is commonly used for?
- Looking up network addresses in the routing table as part of the process of forwarding a packet to a destination.
- Building the routing table.
What does DHCP stand for?
Dynamic Host Configuration Protocol
What is DHCP
The process a device takes when connected into a network that obtains an IP address for itself on the local network, sets up an appropriate default route, and connects itself to a local DNS server.
