IP Addressing Flashcards
IP
Internet Protocol address
Numerical label to identify communication devices on network
Layer 3
IPv4 or IPv6
IPv4 format
32 bits in length
Four 8 bit octets
Subnet mask
Defines network portion
Network portion if binary 1
Host portion if binary 0
Classful Mask
Using default subnet mask
255.0.0.0
Class A IP
First Octet: 1 - 126
Classful Mask decimal: 255.0.0.0
Classful Mask prefix: /8
Class B IP
First Octet: 128 - 191
Classful Mask decimal: 255.255.0.0
Classful Mask prefix: /16
Class C IP
First Octet: 192 - 223
Classful Mask decimal: 255.255.255.0
Classful Mask prefix: /24
Class D IP
First Octet: 224 - 239
Classful Mask decimal: n/a
Classful Mask prefix: n/a
Routable IPs
Publicly-routable IP addresses
Managed by ICANN
Purchased through ISP
ICANN
Internet Corporation for Assigned Names and Numbers
Private IPs
Can be used by anyone
Not routable outside LAN
NAT
Network Address Translation
Allows routing of private IPs through a public IP
Private Class A IP
Address Range: 10.0.0.0 - 10.255.255.255
Default subnet mask: 255.0.0.0
Private Class B IP
Address Range: 172.16.0.0 - 171.31.255.255
Default subnet mask: 255.255.0.0
Private Class C IP
Address Range: 192.168.0.0 - 192.169.255.255
Default subnet mask: 255.255.255.0
Loopback addresses
127.x.x.x
Refer to device itself - used for testing
Commonly 127.0.0.1
APIPA
Automatic Private IP Addresses
Dynamically assigned by OS when DHCP server unavailable
Range of 169.254.x.x
Non-routable
IPv4 Unicast
Data travels from single source to single destination
IPv4 Multicast
Data travels from single source to multiple specific destinations
IPv4 Broadcast
Data travels from single source to all devices on destination network
Static IP assignment
Simple
Time consuming
Human error
Impractical for large networks
Dynamic IP assignment
Quick
Easy
Less confusing
Simple for large networks
Information assigned from static or dynamic IP assignment
IP address
Subnet mask
Default gateway
Server addresses
DHCP
Dynamic Host Control Protocol
Assigns IP from assignable pool (scope)
Provides clients with IP, subnet mask, default gateway, DNS server, WINS server, and variables for VoIP
IP leased for given amount of time
Zeroconfig
Zero Configuration
Assigning link-local IP addresses
Resolving computer names to IP addresses without need for DNS server - mDNS (Multicast DNS)
Locating network services
Subnetting
Dividing up large network into smaller networks
Barrowing bits from original host portion and adding them to network portion
Number of created subnets formula
= 2^s
Where S is number of barrowed bits
Number of assignable IP addresses formula
=2^h-2
Where h is number of host bits
CIDR
Classless Interdomain Routing
Used to summarize contiguous networks as single route
Route aggregation
VLSM
Variable Length Subnet Masking
Allows subnets of various sizes to be used
Subnetting of subnets
Requires protocol that supports it: RIPv2, OSPF, IS-IS, EIGRP, BGP
IPv6
More addresses
No broadcasts
No fragmentation
Simplified header (5 fields instead of 12)
IPv6 address structure
128 bits
Each hexadecimal is 4 bits
IPv6 address types
Globally routable unicast addresses: begins with 2000 to 3999
Link local address: begins with FE80
Multicast address: begins with FF
Does IPv6 need DHCP?
IPv6 uses auto config to discover current network
Selects its own host ID based on MAC address
Uses NDP to learn layer 2 addresses on the network
NDP
Neighbor Discovery Protocol Used to learn layer 2 addresses on network Performs: Router solicitation Router advertisement Neighbor solicitation Neighbor advertisement Redirect
Router solicitation
Host sends message to locate routers on link
Router advertisement
Routers advertise their presence periodically and in response to solicitation
Neighbor solicitation
Used by nodes to determine link layer addresses
Neighbor advertisement
Used by nodes to respond to solicitation messages
IPv6 Unicast
Same as IPv4 but with IPv6 addresses
IPv6 Multicast
Same as IPv4 but with IPv6 addresses
IPv6 Anycast
One host initiates efficient updating of router tables for group of hosts