IT Management & Cyber Security

VPC Network Access Control Lists (NACL) functions as a firewall in that it contains inbound and outbound rules to allow traffic based on a source or destination CIDR, protocol, and port. Also, each  VPC   has a default NACL that can’t be deleted. But the similarities end there. A NACL differs from a security group in many respects. Instead of being attached to an ENI, a NACL is attached to a subnet. The NACL associated with a subnet controls what traffic may enter and exit that subnet. This means that NACLs can’t be used to control traffic between instances in the same subnet. If you want to do that, you have to use security groups. A subnet can have only one NACL associated with it. When you create a new subnet in a VPC, the VPC’s default NACL is associated with the subnet by default. You can modify the default NACL, or you can create a new one and associate it with the subnet. You can also associate the same NACL with multiple  subnets , provided those subnets a...

Amazon Simple Storage Service (S3) is where individuals, applications, and a long list of AWS services keep their data. It’s an excellent platform for the following: – Maintaining backup archives, log files, and disaster recovery images – Running analytics on big data at rest – Hosting static websites S3 provides inexpensive and reliable storage that can, if necessary, be closely integrated with operations running within or external to  Amazon web services . This isn’t the same as the operating system volumes you learned about in the previous chapter: those are kept on the block storage volumes driving your  EC2 instances . S3, by contrast, provides a space for effectively unlimited object storage. What the difference is between object and block storage? With block-level storage, data on a raw physical storage device is divided into individual blocks whose use is managed by a file system. NTFS is a common file system used by Windows, while Linux might use Btrfs or...