Network ACL

• Network ACL is used to control traffic to the subnets.
• When we create a vpc we get a default Network acl which allows all inbound (incoming/ingress) and outbound connections
  
  
• Rules:
  • Each Subnet must be associated with a network ACL
  • One Network ACL can be associated with multiple subnets in a vpc
  • Network ACLs contains number list of rules
  • These rules are evaluated from the lowest number rule to the highest number rule
  • Lowest Rule number is 1 and highest is 32766
  • We have inbound ACL Rules and outbound ACL Rules
• Each Network ACL Rule has
  • Rule Number
  • Type: The type of traffic
    
  • Protocol:
  • Port Range:
  • Source: this is for inbound rules
  • Destination: this is for outbound rules
  • Allow/Deny: Whether to allow or deny the specified traffic.

* Lets create a NACL which allows all the tcp from our ip address and all traffic from with in vpc and denies the rest

Multiple VPC Scenario

• Create the following vpcs and ec2 instances
  
• open tcp 22 & icmp in security group for both ec2 instances
  
• We need private connectivity between two vpcs in AWS (in same region/different region)
• Establishing private connectivity between two networks is done by using Virtual Private Network (VPN) more specifically we call this as site-to-site VPN.
• We need to explore on how to connect
  • between two VPCs
  • between VPC and your organization (on-premises) network.