1.4 Pt 2 Flashcards
(8 cards)
IPv6 Addressing and Subnetting
2A00:DDDD:1111/48 from ISP
2A00:DDDD:1111:0001:0000:0000:0000:0001
First 3 dual octets provided by IANA/RIR/ISP, 48 bits are Global Routing Prefix
Next 16 bits are local subnet
Last 64 bits are Host ID
16 bit subnets allow 65,536 subnets
First 64 bits are prefix, last 64 bits are host
VLSM (Variable Length Subnet Masks)
Use different subnet masks in the same classful network
- 0.0.0/8 is the class A
- 0.1.0/24 and 10.0.8.0/26 would be the VLSM
Defining Subnets
10.0.0.0
255.0.0.0 Class A, /8
1111.0000.0000.0000
Network=8 host=24
255.255.255.0, 1111.1111.1111.0000, /24
Network=8, subnet=16, host=8
#subnets=2^subnet bits #hosts per subnet=2^host bits -2
Calculating # Subnets # Hosts
Traditional Class C 255.255.255.0 192.168.11.0/26 11111111.11111111.11111111.11000000 N=24, S=2, H=6
#subnets=2^subnet bits=4 #hosts per subnet=2^host bits-2=62
DHCP
Assigns first available from pool
Can create IP reservation by MAC
Static is alternate but time consuming to make changes.
Automatic Private IP Addressing
APIPA
When a client can’t reach DHCP server
A link-local address, no forwarding by routers
Can still communicate to local devices
169.254.1.0 - 169.254.254.255
Client auto assigns and sends ARP request to confirm address isn’t in use
DHCPv6
IPv6 has a link local address automatically so they don’t need to broadcast, can use multicast.
Client DHCPv6 Solicit to [ff02::1:2]:547
Server DHCPv6 Advertise to [client]:546
Client DHCPv6 Request to [ff02::1:2]:547
Sever DHCPv6 Reply to [client]:546
EUI-64 (Extended Unique Identifier)
Automatically assigns static IPv6 address based off MAC.
Split MAC to two 24 bit halves
Put FFFE in the middle (missing 16 bits)
Invert 7th bit. Changes the address from globally unique/universal. Turns the burned in address (BIA) to locally administered address. This is the U/L bit (universal/local)
64bit subnet prefix:3-byte MAC:FFFE:3-byte MAC
