What are the differences between Security Group and Network ACL in AWS?

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Let us begin by learning about a security group in Amazon Web Services (AWS).

Security Group in AWS

A Security group acts as a virtual firewall which controls the traffic for one or more instances whenever we launch an instance, we can specify one or more security groups. Generally, we use the default security group.

If you have requirements that are not met by a security group, we can maintain our own firewall on any of our instances in addition to using security groups. If we need to allow traffic to a window instance we can use Amazon EC2 security group.

AWS security group rules

Each rule is comprised of five fields −

  • Type

  • Protocol

  • Port range

  • Source and

  • Destination

This applies to both inbound and outbound rules. Generally, it is used to protect our EC2 instances.

Network ACL in AWS

Access Control Lists (ACL) are used by different companies which are used to provide security to the network and it also helps to restrict the accessibility of the applications for each individual or group by defining the access control rules.

  • Access Control Lists are used at the network level and they are applicable at the sub net level, therefore ACL's are used at the network level.

  • ACL's are very important to set, since they provide security to the company's information at the network level and also helps to restrict the role of the user and also provide authentication to use the applications.

  • These are the reasons why ACL's are very important to set.

  • Only authorized users have to access the data in the network and others cannot be allowed to view and perform CRUD operations.

  • To achieve this, network authentication is used. It provides the accessibility of data only to the authorized users.

In order to create a custom network ACL and associate it with a subnet, basically, each custom network ACL won’t allow all inbound and outbound traffic until you assign rules.


The major differences between security group and Network ACL in AWS are as follows −

Security GroupNetwork ACL
It enhances a security film to EC2 examples that controller together incoming and outbound circulation at the occurrence equal.NACL correspondingly complements an extra layer of security connected with subnets that controller together inbound and outbound circulation at the subnet equal.
It provisions individual allow instructions, and through avoidance, all the rubrics remain refuted. You cannot reject the law for founding a joining.It supports together permit and reject instructions, and through default, altogether the instructions remain refuted. You essentially complement the regulation which you can moreover permit or reject.
It remains functional to an example individual when you stipulate a security group although initiation an occurrence.Network ACL consumes practical mechanically to altogether the occurrences which are connected with an illustration.
It remains the primary layer of protection.It remains the second layer of protection.
The Security groups are tied to an instance.Network ACLs are tied to the subnet.
Any changes applied to an incoming rule will be automatically applied to the outgoing rule in security groups.In network ACL any changes applied to an incoming rule will not be applied to the outgoing rule.
All the rules are evaluated in security groups before allowing a traffic.NACLs do the same in the number order which is from top to bottom.
Updated on 22-Mar-2022 06:43:02