Networking

Question 1

What principle should be used when setting NACL’s and SG’s?

Answer 1

Principle of Least Privilege, only letting the absolute required ports open

Question 2

Does VPC Support Multicast or Broadcast?

Answer 2

No

Question 3

Describe Stateless and Stateful IP Connections

Answer 3

Stateful stores data and maintains session (eg: FTP and Telnet)
Stateless check the data and act on it, but don’t store it or maintain a session (eg: Firewall< HTTP, DNS)

Question 4

What are ephemeral ports?

Answer 4

Temporary connection ports, used for HTTPD, SSHD, FTPD, etc

Question 5

What is BGP?

Answer 5

Routing protocol for moving traffic between different AS networks (ie: AWS, Google, ISP Networks, etc)

Question 6

How are routes in a route table prioritised?

Answer 6

The most specific route is chosen

Question 7

Is Transit peering supported across VPC’s

Answer 7

No

Question 8

What is transit peering? Does VPC Support it?

Answer 8

Transit peering is data moving between VPC-A to VPC-C without any direct peering request. It isn’t supported

Question 9

How are peering requests accepted?

Answer 9

They must be manually accepted via the console, then routes must be added for each VPC

Question 10

What’s the difference between NAT Instances and NAT Gateways

Answer 10

Gateway’s are a fully managed service, Instances are an unmanaged ec2 instance that you have full control over. NAT Gateway’s are HA by default

Question 11

What is an Egress-Only GW

Answer 11

A GW for allowing outbound IPv6 traffic only. Is stateful, prevents IPv6 inbound

Question 12

What routing protocols does AWS support other than BGP

Answer 12

None

Question 13

What are the 2 ways of making Direct Connect redundant?

Answer 13

Cheap: Add a VPN Connection
Expensive: Add a second Direct Connect connection

Question 14

What’s the difference between Horizontal and Vertical Scaling?

Answer 14

Horizontal is adding new resources, Vertical is increasing the capacity of existing resources

Question 15

How are IGW’s scaled? Are they Redundant? Do they have bandwidth constraints?

Answer 15

IGW’s are Horizontally scaled
Yes they’re redundant
No bandwidth constraints

Question 16

Do NAT’s have bandwidth constraints

Answer 16

Yes, they do

Question 17

Can VPC’s have multiple NAT’s across AZ’s and Subnets? If so, how and why?

Answer 17

Yes, must define routes properly, useful for adding scale and redundancy

Question 18

Explain Sticky Sessions

Answer 18

Tool within ALB’s. Uses cookies to ensure a user/session goes to the same server within ALB’s target group.

Question 19

What are the 3 Load Balancer types and which OSI layer do they work on

Answer 19

Application LB - Layer 7 / Application
Network LB - Layer 3 / Network
Classical LB - Layer 4 / TCP IP

Question 20

Are Mesh or Hub & Spoke architectures supported?

Answer 20

Yes, with proper NACL and Routing setup