1.0 Networking Fundamentals
1.4 Subnets and IP Addressing Schemes
Binary Math
128 64 32 16 8 4 2 1 = 255
11111111.11111111.11111111.00000000 = 255.255.255.0
Public vs Private
RFC1918 - Designated private IP address ranges.
Network Address Translation (NAT) - When a device changes an IP address as it crosses through a network.
Port Address Translation (PAT) - Use of ports to designate which device is trying to communicate from a network.
IPv4 - OSI layer 3 address, consists of a 4 octet address, subnet, and gateway to communicate.
IPv6 - OSI layer 3 address, doesn’t use Broadcast, makes use of eight groups of four hexadecimal digits for addressing.
Automatic Private IP Addressing (APIPA) - Link local address, not able to communicate outside of the subnet, often a sign that DHCP failed to provide an IP address to the host.
Extended Unique Identifier (EUI-64) - IPv6 address configured based on a MAC address.
Multicast - Used extensively in IPv6, sends data to all devices wanting to receive the data.
Unicast - One to one, sending data between two systems.
Anycast - One to one-of-many, Sends data to an arbitrary system on a network.
Broadcast - Sending data to all systems on a network, limited by broadcast domain scope.
Link Local - Network address that is only able to communicate within a subnet (APIPA).
Loopback - 127.x.x.x, IP address range that represents the local host on a network.
Default Gateway - IP address that is used to allow a device to communicate beyond the subnet.
IPv4 Subnetting
Classless (variable-length subnet mask) - Subnetting a network into specific sizes based on the subnet mask itself instead of being based on an IP address class designation.
Classful - Subnetting architecture where an IP address can designate your subnet.
Classless Inter-Domain Routing (CIDR) notation - Slash notation, used as a quickhand for subnet masking, the number represents how many bits are in use for the network address vs host address. (255.255.255.0 = 11111111.11111111.11111111.00000000 = /24)
IPv6 Concepts
Tunneling
6to4 Addressing - Sends IPv6 over IPv4, creates an IPv6 address on an IPv4 one, no NAT support, requires relay routers.
4in6 Tunneling - Tunnel IPv4 through IPv6 network.
Teredo - Tunnels IPv6 through NATed IPv4, end-to-end IPv6 through IPv4
Miredo - Open-source Teredo for Linux/Mac OSx
Dual Stack - Router runs both IPv4 and IPv6 simultaneously.
Shorthand Notation - Leading zeros can be removed, groups of zeros can be abbreviated with ::
Router Advertisement - No ARP in IPv6, uses NDP (Neighbor Discovery Protocol)
Neighbor Solicitation (NS) - Multicast used to find other devices
Neighbor Advertisement (NA) - Device response to NS
Discover Routers - Router Solicitation (RS) and Router Advertisement (RA)
Stateless Address Autoconfiguration (SLAAC) - Auto configures a static IPv6 address without a DHCP server.
DAD (Duplicate Address Detection) - Used to detect IP conflicts/duplicates
Virtual IP (VIP) - IP address assigned to a virtual machine.
Subinterfaces - Virtual network interface (connection), a parent interface is divided into two or more virtual interfaces which you can assign an IP address to.
