Virtual Networks

Question 1

Creating a cloud only Virtual Network

Answer 1

1) using the Azure management portal, Azure PowerShell, and xplat-cli.
2) create multiple subnets to improve performance

Question 2

CIDR

Answer 2

1) Classless Inter-Domain Routing (CIDR) notation
2) Shorthand representation of subnet mask
3) 10.0.0.0 / 8(number of bits) -> subnet of 255.0.0.0
4) Address from 10.0.0.0 to 10.255.255.255

Question 3

IP addresses

Answer 3

1) a public-facing virtual IP (VIP) address

2) an internal dynamic IP (DIP)

Question 4

VIP

Answer 4

1) comes from a pool of IP addresses managed by Microsoft

2) It is not assigned directly to the VM. Instead, it’s assigned to the Cloud Service that contains the VM

Question 5

Reserve VIP

Answer 5

1) upto 20 VIPs can be reserved

2) to assign static IPs to your VM

Question 6

Internal Dynamic IP

Answer 6

The DIP address is a dynamic IP address associated with your VM. A DIP is assigned by DHCP with a near-infinite lease. So, it remains stable as long as you don’t stop or deallocate the machine

Question 7

static IP address

Answer 7

1) If your VM resides in a virtual network, you can assign a static IP address to it
2) when you set up a domain controller or a Domain Name System (DNS) server on your virtual network, you’ll need to assign static IPs to these machines because both services require static IP addresses.

Question 8

Instance-Level Public IP (PIP) Address

Answer 8

A PIP, on the other hand, is directly assigned to a VM. PIP is appropriate for workloads that need a large number of ports to be opened, such as passive FTP.

Question 9

Name resolution and DNS servers

Answer 9

1) VMs on the same network can address one another by DIP addresses.
2) Azure provides a built-in hostname resolution for VMs and role instances within the same cloud service
3) for VMs across multiple cloud services, you’ll need to set up your own DNS server.

Question 10

Host Names and FQDN

Answer 10

1) you can define the VM host name by using the vmName property in the service configuration file.
2) In this case, Azure will append an instance number to the name to distinguish different role instances
3) DNS name is assigned to the machine with the format [machine name].cloudapp.net

Question 11

VM End points

Answer 11

1) VIP public ports
2) goes to load balancer
3) load balancer forwards to DIP:private port

Question 12

Network ACLs

Answer 12

ACL provides the ability to selectively permit or deny traffic to a VM endpoint. An ACL comprises an ordered list of rules that either permit or deny traffic to the endpoint. Packets are filtered on the hosting server before they can reach your VM

Question 13

NSG

Answer 13

IP ranges are represented by named tags. There are three default tags:
1) VIRTUAL_NETWORK
2) AZURE_LOADBALANCER 
3) INTERNET 
Blocked by default

Question 14

NSG

Answer 14

1) ACLs are applied to traffic to a specific VM endpoint, whereas NSGs are applied to all traffic that is inbound and outbound on the VM.
2) ACLs are associated to a VM endpoint, whereas NSGs are associated to a VM, or a subnet within a virtual network.
3) You cannot use both ACL and NSG on the same VM instance. You must first remove all endpoint ACLs before you can associate an NSG.