IP Addressing Flashcards
ipv4
32 bits
4-bit octets
subnet mask
defines network portion network = 1 = 255 host = 0 ex: 1.2.3.4 w/ 255.255.255.0 network = 1.2.3 host = 4
class a
first octet: 1-126
255.0.0.0
/8
class b
first octet: 128-191
255.255.0.0
/16
class c
first octet: 192-223
255.255.255.0
/24
class d
first octet: 224-239
n/a
n/a
private ips
used by anyone
not routable outside network
class a: 10.0.0.0-10.255.255.255 class b: 172.16.0.0-172.31.255.255 class c: 192.168.0.0-192.168.255.255
nat
network address translation
allows for routing of private ips through a public ip
how most home networks work
loopback ip
ipv4 127.0.0.0/8
ipv6 ::1/128
apipa
automatic private ip addresses
dynamically assigned by os when dhcp server is unavailable
169.254.0.0/16
vip/vipa
virtual ip/address
ip that does not correlate to an actual physical network interface
subinterfaces
virtual interface that is created by dividing up one physical interface into multiple logical interfaces
unicast
ipv4 and ipv6
data travels from a single source to single destination
multicast
ipv4 and ipv6
data travels from a single source to multiple but specific destinations
broadcast
just ipv4
data travels from a single source to all devices on a destination network
static ip assignment
simple, time consuming, prone to human error, impractical for large network
dynamic ip assignment
quicker, easier, less confusing, simplistic for large networks
components of dhcp
ip addr
subnet mask
default gateway
dns or wins server
wins: windows internet name service - converts netbios computer name into ip addr
dhcp
dynamic host configuration protocol
assigns ip from an available scope
can use ip addr management software to keep track of those assigned
ip, subnet mask, default gateway, dns
each is given ttl and returned to pool when expired
subnetting
default classful subnet masks are not always the best choice
borrow bits from host portion and add them to network
more efficient, more security, bandwidth control
/25
255.255.255.128 –> 11111111.11111111.11111111.10000000
2 subnet
128 ips
/26
255.255.255.192 –> 11111111.11111111.11111111.11000000
4 subnet
64 ips
/27
255.255.255.224 –> 11111111.11111111.11111111.11100000
8 subnet
32 ips
/28
255.255.255.240 –> 11111111.11111111.11111111.11110000
16 subnet
16 ips
/29
255.255.255.248 –> 11111111.11111111.11111111.11111000
32 subnet
8 ips
/30
255.255.255.252 –> 11111111.11111111.11111111.11111100
64 subnet
4 ips
subnetting formulas
number of created subnets = 2^s
*s = # of borrowed bits
number of assignable ips = 2^h -2
*h = # of host bits
why subtract 2?
require 2 for network id (first) and broadcast ip (last)
total ips vs available ips(subtract network and broadcast)
cidr
classless interdomain routing
multiple routes can be displayed as single address
aka route aggregation
vlsm
variable-length subnet masking
allows subnets of varous sizes
requires routing protocols : ripv2, ospf, is-is, eigrp, bgp
ipv6
were running out of ipv4 340 undecillion addresses no broadcasts or fragmentation smaller header than ipv4 can coexist with ipv4 128bit 32 hex digits -> 8 sets of 4 hex digits ex: 2018:0:0:0000:0:000:1234:ae44 condense 0s --> 2018::1234:ae44
slaac
stateless address autoconfiguration
dhcp for ipv6
Discovers the current network that an interface is located on and then
select its own host ID based on its MAC address using the EUI64 process
ndp
neighbor discovery protocol
ipv6 version of arp and broadcast; used to learn layer 2 addresses
router solicitation - host sends message to find routers
router advertisement - router advertise periodically and in response to solicitation
neighbor solicitation - used by nodes to determine mac addr
neighbor advertisement - used by nodes to respond to solicitation
redirect - routers tell host of better first hop routers
anycast
for ipv6
let one host initiate updating of router tables for a group of hosts
