2.5 IPv4 and IPv6 Flashcards
What are the two protocols used for most things we do regarding the internet?
IPv4 and IPv6. Supported by most OS’s. Can help devices communicate with other
IPv4 addresses are built to what OSI layer?
- It’s built of four decimal point segments ( example:192.168.1.131). Each segment consists of 32 bits, so the total size of an IPv4 address is 4 bytes. The max value of a segment is 255 (255.255.255.255 is the highest).
Why did we create IPv6 addresses?
The popularity of the internet. They have 8 different groups with 16 bits per group. This totals 128 bits or 16 bytes, so 6.8 billion people could each have 5 (with 30 0’s) total IP addresses. IPv6 addresses are shown in hexadecimal format (fe80:5d18:652:cffd:8f52). Because these are hard to remember, DNS is important
How are the first 64 and last 64 bits of an IPv6 address created?
The first 64 bits are generally the network prefix. The last 64 are are the host network address
What’s something you want to consider when assigning IPv4 addresses to your local network?
Each device needs a unique address (ex 192.168.1.165) and a subnet mask (ex 255.255.255.0). Subnet masks help the device determine which subnet they’re connected to. You need both of these parameters to complete IP assignment
What is a default gateway?
The router that allows you to communicate outside of your local subnet. The default gateway must be an IP address on the local subnet
What is the historical protocol that automatically assigned IP addresses to devices?
BOOTP, the bootstrap protocol, created 1993. It was limited in features so we launched DHCP in 1997. This updates IP addresses automatically for almost all devices
What is the four step processes that provides an IP configuration to your device?
DORA
Discover (find a DHCP server)
Offer (get an offer)
Request (lock in the offer)
Acknowledge (DHCP server confirms address and assigns everything your device needs)
How does the discover phase of DORA work?
Client workstation sends a broadcast through UDP port 67 on the switch
Routers normally don’t send broadcasts through themselves. How can we enable that to happen?
Enable DHCP relay, this turns the router into an IP helper
How does the offer phase of DORA work?
Client receives the offer through a broadcast sent over UDP 68. If multiple offers were sent, it examines the offers and makes a decision on which offer to accept for IP address assignment
How does the request phase of DORA work?
Client sends its formal request back through the switch to the DHCP servers with UDP 67. The offer only goes to one DHCP server even if multiple offers were involved
How does the acknowledge phase of DORA work?
DHCP server broadcasts a message back through the switch to the client workstation over UDP port 68 confirming that the request has been acknowledged. The device can now assign itself the IP address settings agreed upon
How often does a device go through the DORA process?
Every time a device needs to connect to the network and obtain an IP address from a DHCP server
What is a pool of IP addresses?
A range of IP addresses that was created when the DHCP servers were first configured
