VPC 2

Question 1

DHCP

How does DHCP start out for new hosts?

Answer 1

Layer 2 broadcast (frames and MAC addresses), gets Layer 3 config

Question 2

DHCP

8 things DHCP gives a new host?

Answer 2

IP address, subnet mask, default gateway, DNS servers, DNS domain name, NTP servers, NetBios name & type

Question 3

DHCP

What is AmazonProividedDNS under the covers?

Answer 3

Just a Route53 Resolver mapped to your VPC

Question 4

DHCP

How do you have a custom domain name for hosts in your VPC?

Answer 4

Have to run your own DNS server (and use DHCP Options Sets to register them)

Question 5

DHCP

Edit a DHCP Option Set, how does this affect current hosts?

Answer 5

Trick question: DHCP Option Sets are immutable

Question 6

DHCP

Can you share a DHCP Options Set across multiple VPCs?

Answer 6

Yes

Question 7

DHCP

Change DHCP Option Set assigned to a VPC. Affect on existing hosts?

Answer 7

YES, but only when the host does a RENEW on it’s DHCP info

Question 8

DHCP

How do you set the IP mask in a DHCP Option Set?

Answer 8

Can’t: set based on the CIDR range of the VPC

Question 9

DHCP

How do you set the default gateway in a DHCP Option set?

Answer 9

Can’t: it’s always the base CIDR for a subnet “+ 1”.

Question 10

DHCP

How do you set the DNS servers in a DHCP Option Set?

Answer 10

Just click Edit…normal fields.

Question 11

DHCP

Where is the default AmazonProvidedDNS on the network?

Answer 11

Base CIDR of the VPC “+ 2”

Question 12

DHCP

Wait, AmazonProvidedDNS is on VPC+2 and not subnet+2?

Answer 12

Subnet+2 is reserved in every subnet, but the actual Route53 Resolver is on VPC+2