118 lines
6.5 KiB
Markdown
118 lines
6.5 KiB
Markdown
# VPC
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- [VPC](#vpc)
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- [VPC & Subnets Primer](#vpc--subnets-primer)
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- [Internet Gateway & NAT Gateways](#internet-gateway--nat-gateways)
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- [Network ACL & Security Groups](#network-acl--security-groups)
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- [Network ACLs vs Security Groups](#network-acls-vs-security-groups)
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- [VPC Flow Logs](#vpc-flow-logs)
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- [VPC Peering](#vpc-peering)
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- [VPC Endpoints](#vpc-endpoints)
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- [Site to Site VPN & Direct Connect](#site-to-site-vpn--direct-connect)
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- [Transit Gateway](#transit-gateway)
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- [VPC Summary](#vpc-summary)
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## VPC & Subnets Primer
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- VPC -Virtual Private Cloud: private network to deploy your resources (regional resource)
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- Subnets allow you to partition your network inside your VPC (Availability Zone resource)
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- A public subnet is a subnet that is accessible from the internet
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- A private subnet is a subnet that is not accessible from the internet
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- To define access to the internet and between subnets, we use Route Tables.
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## Internet Gateway & NAT Gateways
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- Internet Gateways helps our VPC instances connect with the internet
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- Public Subnets have a route to the internet gateway.
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- NAT Gateways (AWS-managed) & NAT Instances (self-managed) allow your instances in your Private Subnets to access the internet while remaining private
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## Network ACL & Security Groups
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- NACL (Network ACL)
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- A firewall which controls traffic from and to subnet
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- Can have ALLOW and DENY rules
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- Are attached at the Subnet level
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- Rules only include IP addresses
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- Security Groups
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- A firewall that controls traffic to and from an ENI / an EC2 Instance
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- Can have only ALLOW rules
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- Rules include IP addresses and other security groups
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### Network ACLs vs Security Groups
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| Security Group | Network ACL |
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| ------------------------------------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------- |
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| Operates at the instance level | Operates at the subnet level |
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| Supports allow rules only | Supports allow rules and deny rules |
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| Is stateful: Return traffic is automatically allowed, regardless of any rules | Is stateless: Return traffic must be explicitly allowed by rules |
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| We evaluate all rules before deciding whether to allow traffic | We process rules in number order when deciding whether to allow traffic |
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| Applies to an instance only if someone specifies the security group when launching the instance, or associates the security group with the instance later on | Automatically applies to all instances in the subnets it's associated with (therefore, you don't have to rely on users to specify the security group) |
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<https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Security.html>
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## VPC Flow Logs
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- Capture information about IP traffic going into your interfaces:
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- VPC Flow Logs
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- Subnet Flow Logs
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- Elastic Network Interface Flow Logs
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- Helps to monitor & troubleshoot connectivity issues. Example:
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- Subnets to internet
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- Subnets to subnets
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- Internet to subnets
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- Captures network information from AWS managed interfaces too: Elastic Load Balancers, ElastiCache, RDS, Aurora, etc…
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- VPC Flow logs data can go to S3 / CloudWatch Logs
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## VPC Peering
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- Connect two VPC, privately using AWS’ network
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- Make them behave as if they were in the same network
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- Must not have overlapping CIDR (IP address range)
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- VPC Peering connection is not transitive (must be established for each VPC that need to communicate with one another)
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## VPC Endpoints
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- Endpoints allow you to connect to AWS Services using a private network instead of the public www network
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- This gives you enhanced security and lower latency to access AWS services
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- VPC Endpoint Gateway: S3 & DynamoDB
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- VPC Endpoint Interface: the rest
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## Site to Site VPN & Direct Connect
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- Site to Site VPN
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- Connect an on-premises VPN to AWS
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- The connection is automatically encrypted
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- Goes over the public internet
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- On-premises: must use a Customer Gateway (CGW)
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- AWS: must use a Virtual Private Gateway (VGW)
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- Direct Connect (DX)
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- Establish a physical connection between on-premises and AWS
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- The connection is private, secure and fast
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- Goes over a private network
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- Takes at least a month to establish
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## Transit Gateway
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- For having transitive peering between thousands of VPC and on-premises, hub-and-spoke (star) connection
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- One single Gateway to provide this functionality
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- Works with Direct Connect Gateway, VPN connections
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## VPC Summary
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- VPC: Virtual Private Cloud
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- Subnets:Tied to an AZ, network partition of the VPC
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- Internet Gateway: at the VPC level, provide Internet Access
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- NAT Gateway / Instances: give internet access to private subnets
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- NACL: Stateless, subnet rules for inbound and outbound
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- Security Groups: Stateful, operate at the EC2 instance level or ENI
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- VPC Peering: Connect two VPC with non overlapping IP ranges, nontransitive
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- VPC Endpoints: Provide private access to AWS Services within VPC
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- VPC Flow Logs: network traffic logs
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- Site to Site VPN: VPN over public internet between on-premises DC and AWS
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- Direct Connect: direct private connection to AWS
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- Transit Gateway: Connect thousands of VPC and on-premises networks together
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* * *
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[👈 Cloud Monitoring](./cloud_monitoring.md) [Home](../README.md) [Security & Compliance 👉](./security_compliance.md)
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