AWS AWSEC2 documentation change
Summary
Added new 'Multiple IP addresses' section with use cases and operational details, updated terminology from 'Multiple IP addresses' to 'Secondary IP addresses', and corrected documentation links
Security assessment
The changes primarily expand documentation about secondary IP address management without indicating any security vulnerability remediation. The mention of security groups applying to network interfaces rather than individual IPs is an existing security consideration, not a new security feature or vulnerability fix.
Diff
diff --git a/AWSEC2/latest/UserGuide/using-instance-addressing.md b/AWSEC2/latest/UserGuide/using-instance-addressing.md index c683b76ce..e877654ee 100644 --- a//AWSEC2/latest/UserGuide/using-instance-addressing.md +++ b//AWSEC2/latest/UserGuide/using-instance-addressing.md @@ -5 +5 @@ -Private IPv4 addressesPublic IPv4 addressesPublic IPv4 address optimizationIPv6 addressesEC2 instance hostnamesLink-local addresses +Private IPv4 addressesPublic IPv4 addressesPublic IPv4 address optimizationIPv6 addressesMultiple IP addressesEC2 instance hostnamesLink-local addresses @@ -22,0 +23,2 @@ When you launch an EC2 instance, you specify a VPC and a subnet. The instance re + * Multiple IP addresses + @@ -31 +33 @@ When you launch an EC2 instance, you specify a VPC and a subnet. The instance re - * [Multiple IP addresses for your EC2 instances](./MultipleIP.html) + * [Secondary IP addresses for your EC2 instances](./instance-secondary-ip-addresses.html) @@ -57 +59 @@ VPC subnets can be one of the following types: -When you launch an EC2 instance into an IPv4-only or dual stack (IPv4 and IPv6) subnet, the instance receives a primary private IP address from the IPv4 address range of the subnet. For more information, see [IP addressing](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-ip-addressing.html) in the _Amazon VPC User Guide_. If you don't specify a primary private IP address when you launch the instance, we select an available IP address in the subnet's IPv4 range for you. Each instance has a default network interface (index 0) that is assigned the primary private IPv4 address. You can also specify additional private IPv4 addresses, known as _secondary private IPv4 addresses_. Unlike primary private IP addresses, secondary private IP addresses can be reassigned from one instance to another. For more information, see [Multiple IP addresses for your EC2 instances](./MultipleIP.html). +When you launch an EC2 instance into an IPv4-only or dual stack (IPv4 and IPv6) subnet, the instance receives a primary private IP address from the IPv4 address range of the subnet. For more information, see [IP addressing](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-ip-addressing.html) in the _Amazon VPC User Guide_. If you don't specify a primary private IP address when you launch the instance, we select an available IP address in the subnet's IPv4 range for you. Each instance has a default network interface (index 0) that is assigned the primary private IPv4 address. You can also specify additional private IPv4 addresses, known as _secondary private IPv4 addresses_. Unlike primary private IP addresses, secondary private IP addresses can be reassigned from one instance to another. For more information, see Multiple IP addresses. @@ -71 +73 @@ You can control whether your instance receives a public IP address as follows: - * Enable or disable the public IP addressing feature during launch. This overrides the subnet's public IP addressing attribute. For more information, see [Assign a public IPv4 address during instance launch](./working-with-ip-addresses.html#public-ip-addresses). + * Enable or disable the public IP addressing feature during launch. This overrides the subnet's public IP addressing attribute. For more information, see [Assign a public IPv4 address at launch](./working-with-ip-addresses.html#public-ip-addresses). @@ -189,0 +192,44 @@ For more information about reserved IPv6 address ranges, see [IANA IPv6 Special- +## Multiple IP addresses + +You can specify multiple private IPv4 and IPv6 addresses for your instances. The number of network interfaces and private IPv4 and IPv6 addresses that you can specify for an instance depends on the instance type. For more information, see [Maximum IP addresses per network interface](./AvailableIpPerENI.html). + +###### Use cases + + * Host multiple websites on a single server by using multiple SSL certificates on a single server and associating each certificate with a specific IP address. + + * Operate network appliances, such as firewalls or load balancers, that have multiple IP addresses for each network interface. + + * Redirect internal traffic to a standby instance in case your instance fails, by reassigning the secondary IP address to the standby instance. + + + + +###### How multiple IP addresses work + + * You can assign a secondary private IPv4 address to any network interface. + + * You can assign multiple IPv6 addresses to a network interface that's in a subnet that has an associated IPv6 CIDR block. + + * You must choose a secondary IPv4 address from the IPv4 CIDR block range of the subnet for the network interface. + + * You must choose IPv6 addresses from the IPv6 CIDR block range of the subnet for the network interface. + + * You associate security groups with network interfaces, not individual IP addresses. Therefore, each IP address you specify in a network interface is subject to the security group of its network interface. + + * Multiple IP addresses can be assigned and unassigned to network interfaces attached to running or stopped instances. + + * Secondary private IPv4 addresses that are assigned to a network interface can be reassigned to another one if you explicitly allow it. + + * An IPv6 address cannot be reassigned to another network interface; you must first unassign the IPv6 address from the existing network interface. + + * When assigning multiple IP addresses to a network interface using the command line tools or API, the entire operation fails if one of the IP addresses can't be assigned. + + * Primary private IPv4 addresses, secondary private IPv4 addresses, Elastic IP addresses, and IPv6 addresses remain with a secondary network interface when it is detached from an instance or attached to an instance. + + * Although you can't detach the primary network interface from an instance, you can reassign the secondary private IPv4 address of the primary network interface to another network interface. + + + + +For more information, see [Secondary IP addresses for your EC2 instances](./instance-secondary-ip-addresses.html). +