Authorize inbound traffic for your Linux instances

Security groups enable you to control traffic to your instance, including the kind of traffic that can reach your instance. For example, you can allow computers from only your home network to access your instance using SSH. If your instance is a web server, you can allow all IP addresses to access your instance using HTTP or HTTPS, so that external users can browse the content on your web server.

Your default security groups and newly created security groups include default rules that do not enable you to access your instance from the internet. For more information, see Default security groups and Custom security groups. To enable network access to your instance, you must allow inbound traffic to your instance. To open a port for inbound traffic, add a rule to a security group that you associated with your instance when you launched it.

To connect to your instance, you must set up a rule to authorize SSH traffic from your computer's public IPv4 address. To allow SSH traffic from additional IP address ranges, add another rule for each range you need to authorize.

If you've enabled your VPC for IPv6 and launched your instance with an IPv6 address, you can connect to your instance using its IPv6 address instead of a public IPv4 address. Your local computer must have an IPv6 address and must be configured to use IPv6.

If you need to enable network access to a Windows instance, see Authorizing inbound traffic for your Windows instances in the Amazon EC2 User Guide for Windows Instances.

Before you start
 
Decide who requires access to your instance; for example, a single host or a specific network that you trust such as your local computer's public IPv4 address. The security group editor in the Amazon EC2 console can automatically detect the public IPv4 address of your local computer for you. Alternatively, you can use the search phrase "what is my IP address" in an internet browser, or use the following service: Check IP. If you are connecting through an ISP or from behind your firewall without a static IP address, you need to find out the range of IP addresses used by client computers.

Warning
If you use 0.0.0.0/0, you enable all IPv4 addresses to access your instance using SSH. If you use ::/0, you enable all IPv6 addresses to access your instance. You should authorize only a specific IP address or range of addresses to access your instance.
Decide whether you'll support SSH access to your instances using EC2 Instance Connect. If you will not use EC2 Instance Connect, consider uninstalling it or denying the following action in your IAM policies: ec2-instance-connect:SendSSHPublicKey. For more information, see Uninstall EC2 Instance Connect and Configure IAM Permissions for EC2 Instance Connect.

Add a rule for inbound SSH traffic to a Linux instance
 
Security groups act as a firewall for associated instances, controlling both inbound and outbound traffic at the instance level. You must add rules to a security group to enable you to connect to your Linux instance from your IP address using SSH.

To add a rule to a security group for inbound SSH traffic over IPv4 (console)
Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.
From the top navigation bar, select a Region for the security group. Security groups are specific to a Region, so you should select the same Region in which you created your instance.
In the navigation pane, choose Instances.
Select your instance and, in bottom half of the screen, choose the Security tab. Security groups lists the security groups that are associated with the instance. Inbound rules displays a list of the inbound rules that are in effect for the instance.
For the security group to which you'll add the new rule, choose the security group ID link to open the security group.
On the Inbound rules tab, choose Edit inbound rules.
On the Edit inbound rules page, do the following:

Choose Add rule.
For Type, choose SSH.
For Source, choose My IP to automatically populate the field with the public IPv4 address of your local computer.

Alternatively, for Source, choose Custom and enter the public IPv4 address of your computer or network in CIDR notation. For example, if your IPv4 address is 203.0.113.25, enter 203.0.113.25/32 to list this single IPv4 address in CIDR notation. If your company allocates addresses from a range, enter the entire range, such as 203.0.113.0/24.

For information about finding your IP address, see Before you start.
Choose Save rules.
If you launched an instance with an IPv6 address and want to connect to your instance using its IPv6 address, you must add rules that allow inbound IPv6 traffic over SSH.

To add a rule to a security group for inbound SSH traffic over IPv6 (console)
Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.
From the top navigation bar, select a Region for the security group. Security groups are specific to a Region, so you should select the same Region in which you created your instance.
In the navigation pane, choose Instances.
Select your instance and, in bottom half of the screen, choose the Security tab. Security groups lists the security groups that are associated with the instance. Inbound rules displays a list of the inbound rules that are in effect for the instance.
For the security group to which you'll add the new rule, choose the security group ID link to open the security group.
On the Inbound rules tab, choose Edit inbound rules.
On the Edit inbound rules page, do the following:

Choose Add rule.
For Type, choose SSH.
For Source, choose Custom and enter the IPv6 address of your computer in CIDR notation. For example, if your IPv6 address is 2001:db8:1234:1a00:9691:9503:25ad:1761, enter 2001:db8:1234:1a00:9691:9503:25ad:1761/128 to list the single IP address in CIDR notation. If your company allocates addresses from a range, enter the entire range, such as 2001:db8:1234:1a00::/64.
Choose Save rules.
Note
Be sure to run the following commands on your local system, not on the instance itself. For more information about these command line interfaces, see Access Amazon EC2.
To add a rule to a security group using the command line
Find the security group that is associated with your instance using one of the following commands:

describe-instance-attribute (AWS CLI)

 
aws ec2 describe-instance-attribute --region region --instance-id instance_id --attribute groupSet
Get-EC2InstanceAttribute (AWS Tools for Windows PowerShell)

 
PS C:\> (Get-EC2InstanceAttribute -Region region -InstanceId instance_id -Attribute groupSet).Groups
Both commands return a security group ID, which you use in the next step.
Add the rule to the security group using one of the following commands:

authorize-security-group-ingress (AWS CLI)

 
aws ec2 authorize-security-group-ingress --region region --group-id security_group_id --protocol tcp --port 22 --cidr cidr_ip_range
Grant-EC2SecurityGroupIngress (AWS Tools for Windows PowerShell)

The Grant-EC2SecurityGroupIngress command needs an IpPermission parameter, which describes the protocol, port range, and IP address range to be used for the security group rule. The following command creates the IpPermission parameter:

 
PS C:\> $ip1 = @{ IpProtocol="tcp"; FromPort="22"; ToPort="22"; IpRanges="cidr_ip_range" }
 
PS C:\> Grant-EC2SecurityGroupIngress -Region region -GroupId security_group_id -IpPermission @($ip1)
Assign a security group to an instance
 
You can assign a security group to an instance when you launch the instance. When you add or remove rules, those changes are automatically applied to all instances to which you've assigned the security group.

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