IPv6 Addresses

This topic describes support for IPv6 addressing in your VCN.

Highlights

  • IPv6 addressing is supported for all commercial and government regions.
  • During VCN creation, you choose whether the VCN is enabled for IPv6, or you can enable IPv6 on existing IPv4-only VCNs. You also choose whether each subnet in an IPv6-enabled VCN is enabled for IPv6.
  • IPv6-enabled VCNs can use a /56 IPv6 global unicast address (GUA) prefix allocated by Oracle, or specify a ULA prefix or a BYOIPv6 prefix. This Oracle-assigned /56 prefix is globally routable to the VCN for internet communication, and is equivalent to IPv4 public addressing. All IPv6 enabled subnets are /64. You can either permit or prohibit internet communication to a subnet by specifying the "public/private" subnet level flag.
  • If you use BYOIP, you can import a /48 or larger IPv6 GUA prefix and must assign a /64 prefix or larger to a VCN.
  • You can specify a unique local address (ULA) prefix. This prefix is internally routable within your OCI network, and is equivalent to IPv4 private addressing. With ULA, you can assign a /64 prefix or larger to a VCN.
  • You also choose whether a given VNIC in an IPv6-enabled subnet has IPv6 addresses (up to 32 maximum per VNIC).
  • Only these Networking gateways support IPv6 traffic: dynamic routing gateway (DRG) , local peering gateway (LPG) , and internet gateway .
  • Both inbound- and outbound-initiated IPv6 connections are supported between your VCN and the internet, and between your VCN and your on-premises network. Communication between resources within your VCN or between VCNs is also supported.
  • IPv6 traffic between resources within a region (intra- and inter-VCN) is supported. See other important details in Routing for IPv6 Traffic and Internet Communication.
  • Both FastConnect and Site-to-Site VPN support IPv6 traffic between your VCN and on-premises network. You must configure FastConnect or Site-to-Site VPN for IPv6.

Overview of IPv6 Addresses

Oracle supports dual-stack IPv4/IPv6 addressing for VCNs. Every VCN always supports IPv4, and you can optionally enable IPv6 during VCN creation. You can also add an IPv6 prefix to an IPv4-only VCN while enabling IPv6. Enabling IPv6 for the VCN means that when you create a subnet, you can optionally enable it to also have IPv6 addresses. Therefore a VCN can have a mix of IPv4-only subnets and IPv6-enabled subnets.

After you create a compute instance, you can add an IPv6 address to the VNIC. These IP addresses can be assigned from multiple IPv6 prefixes if they are assigned to the subnet. You can remove an IPv6 address from a VNIC at any time.

IPv6 Prefixes Assigned to an IPv6-Enabled VCN

An IPv6-enabled VCN is dual stack, meaning it has both an IPv4 CIDR and an IPv6 prefix assigned. A VCN can have up to five IPv4 CIDRs and up to five IPv6 prefixes. An IPv6-enabled VCN can use an Oracle-allocated /56 GUA, let you import and assign a BYOIPv6 prefix, or specify a ULA prefix. Oracle can allocate a GUA IPv6 prefix, also referred to here as a globally routable IPv6 prefix. You can also use Bring Your Own IP (BYOIP) to use a /48 prefix. The following table summarizes the options.

IPv4 or IPv6 Use and Size Who Assigns the Address Block Allowed Values
Private IPv4 CIDR

Private communication

/16 to /30

You Typically RFC 1918 range
Globally routable IPv6 prefix

Internet or Private Communication

/56

Oracle

Oracle allocates the VCN's IPv6 prefix.

BYOIP IPv6 prefix

Internet or Private Communication

/64 (minimum)

You IPv6 Global Unicast Addresses (GUA) are always in the range of 2000::/3
IPv6 ULA

Private Communication

/64 (minimum)

You

IPv6 unique local addresses (ULAs) are always in the address range fc00::/7.

Unique Local Addresses (ULA) are globally unique addresses that permit communication between nodes on different links within the same site or between sites. They are administratively segmented and are not for routing on the Internet. RFC 4193 provides more information about ULAs.

Internet Communication

When you enable IPv6 in your VCN, you can choose which types of IPv6 addresses are assigned: Oracle-allocated, BYOIPv6, or ULA. You can then enable IPv6 in subnets (see Task 2: Create a regional IPv6-enabled public subnet) and assign IPv6 addresses to an individual instance's VNICs or load balancers if they were launched in an IPv6-enabled subnet with an IPv6 prefix. You can also determine whether internet communication with IPv6-enabled resources is permitted or prohibited by specifying the subnet is public or private. If an IPv6-enabled resource is assigned a GUA address and is hosted in a public subnet, communication to and from the internet is permitted. If an IPv6-enabled resource is hosted in a private subnet, communication to and from the internet is prohibited even if the resource has a GUA address assigned.

Assignment of IPv6 Addresses to a VNIC

To enable IPv6 for a given VNIC, you assign an IPv6 to the VNIC. These IP addresses can be assigned from multiple IPv6 prefixes if they are assigned to the subnet. As with IPv4, when assigning an IPv6 address, you can specify the particular address you want to use, or let Oracle choose one for you.

You can move an IPv6 address from one VNIC to another in the same subnet.

Format of IPv6 Addresses

IPv6 addresses have 128 bits.

An IPv6 prefix block for a VCN must be /56 in size. The left 56 bits identify the VCN portion of the address. For example:

2001:0db8:0123:7800::/56 (or fd00::/56 for ULA addresses)

An IPv6 prefix block for a subnet must be /64 in size. The right 16 bits in a subnet's prefix identify the subnet portion of the address. In the following example, the 7811 is the unique portion for the subnet:

2001:0db8:0123:7811::/64

In the following ULA example, the 11 is the unique portion for the subnet:

fd00:0:0:11::/64

The right-most 64 bits of an IPv6 address identify the unique portion specific to the particular IPv6 address. For example:

2001:0db8:0123:7811:abcd:ef01:2345:6789

When you assign an IPv6 to a VNIC, you can specify which specific IPv6 address to use (those 64 bits).

Example of Enabling IPv6 in your VCN

In this example, Oracle assigns this prefix: 2001:0db8:0123: 7811::/56.

The following diagram illustrates the VCN and includes two subnets: public subnet 1111 and private subnet 1112.

This image shows an example of IPv4 and IPv6 addresses used in a VCN with an Oracle-provided IPv6 prefix.

Access to the internet is always determined at the subnet level, not at the VNIC level.

VNIC 1 in Subnet 1111 has a primary private IPv4 address (10.0.1.4) with an optional IPv6 address assigned. VNIC 1 has a secondary private IPv4 address (10.0.1.5), also with an optional public IP address assigned.

Since Subnet 1111 has internet access enabled it can only have an internet-routable IPv6 address, which is 2001:0db8:0123:7811:abcd:ef01:2345:0006.

Subnet 1112 is private, which means the VNICs don't have IPv4 or IPv6 access from the internet. The instance using VNIC 2 can still initiate contact with other hosts on the internet and get responses, but won't get uninitiated requests.

Routing for IPv6 Traffic

Both inbound- and outbound-initiated IPv6 connections are supported between your VCN and the internet, and between your VCN and your on-premises network. Communication between resources within your VCN or between VCNs is also supported.

Here are other important details about routing of IPv6 traffic:

  • Currently IPv6 traffic is supported only through these gateways:

    • Dynamic routing gateway (DRG): For access to your on-premises network or other networks outside the region (using remote peering). Both Oracle Cloud Infrastructure FastConnect and Site-to-Site VPN support IPv6 traffic. For more details about IPv6 configuration, see the upcoming sections.
    • Internet gateway: For access to the internet.
    • Local peering gateway: For connecting two VCNs in the same region so that their resources can communicate using private IP addresses without routing the traffic over the internet or through your on-premises network.
  • IPv6 traffic between resources within a region (intra- and inter-VCN) is supported. VCNs are dual-stack. meaning they support IPv4 and can optionally also support IPv6. So, a VCN's route tables support both IPv4 and IPv6 rules in the same table. IPv4 and IPv6 rules must be discretely specified. Rules to route traffic that match a certain IPv6 prefix to the VCN's attached DRG, internet gateway, local peering gateway, or an IPv6 Address (next hop) are supported.

VCN Route Tables and IPv6

The VCN's route tables support both IPv4 rules and IPv6 rules that use a DRG, local peering gateway, or internet gateway as the target. For example, the route table for a given subnet could have these rules:

  • Rule to route traffic that matches a certain IPv4 CIDR to the VCN's attached DRG
  • Rule to route traffic that matches a certain IPv4 CIDR to the VCN's service gateway
  • Rule to route traffic that matches a certain IPv4 CIDR to the VCN's NAT gateway
  • Rule to route traffic that matches a certain IPv6 prefix to the VCN's attached DRG
  • Rule to route traffic that matches a certain IPv6 prefix to the VCN's attached internet gateway

Security Rules for IPv6 Traffic

Like route tables, the VCN's network security groups and security listsSecurity Rulessupport both IPv4 and IPv6 rules. For example, a network security group or security list could have these security rules:

  • Rule to allow SSH traffic from the on-premises network's IPv4 CIDR
  • Rule to allow ping traffic from the on-premises network's IPv4 CIDR
  • Rule to allow SSH traffic from the on-premises network's IPv6 prefix
  • Rule to allow ping traffic from the on-premises network's IPv6 prefix

The default security list in an IPv6-enabled VCN includes default IPv4 rules and the following default IPv6 rules:

  • Stateful ingress: Allow IPv6 TCP traffic on destination port 22 (SSH) from source ::/0 and any source port. This rule makes it easy for you to create a VCN with a public subnet and internet gateway, create a Linux instance, add an internet-access-enabled IPv6, and then immediately connect with SSH to that instance without needing to write any security rules yourself.

    Important

    The default security list does not include a rule to allow Remote Desktop Protocol (RDP) access. If you're using Windows images, add a stateful ingress rule for TCP traffic on destination port 3389 from source ::/0 and any source port.

    See To enable RDP access for more information.

  • Stateful ingress: Allow ICMPv6 traffic type 2 code 0 (Packet Too Big) from source ::/0 and any source port. This rule enables your instances to receive Path MTU Discovery fragmentation messages.
  • Stateful egress: Choosing to allow all IPv6 traffic lets instances initiate IPv6 traffic of any kind to any destination. Notice that instances with an internet-access-enabled IPv6 can talk to any internet IPv6 address if the VCN has a configured internet gateway. And because stateful security rules use connection tracking, the response traffic is automatically allowed regardless of any ingress rules. For more information, see Stateful Versus Stateless Rules.

FastConnect and IPv6

If you use FastConnect , you can configure it so that on-premises hosts with IPv6 addresses can communicate with an IPv6-enabled VCN. In general, you must ensure that the FastConnect virtual circuit has IPv6 BGP addresses, and update the VCN's routing and security rules for IPv6 traffic.

About the IPv6 BGP Addresses

A FastConnect virtual circuit always requires IPv4 BGP addresses, but IPv6 BGP addresses are optional and only required for IPv6 traffic. Depending on how you're using FastConnect, you might be asked to provide the virtual circuit's BGP addresses yourself (both IPv4 and IPv6).

The addresses consist of a pair: one for your end of the BGP session, and another for the Oracle end of the BGP session.

When you specify a BGP address pair, you must include a subnet mask that contains both of the addresses. Specifically for IPv6, the allowed subnet masks are:

  • /64
  • /96
  • /126
  • /127

For example, you could specify 2001:db8::6/64 for the address at your end of the BGP session, and 2001:db8::7/64 for the Oracle end.

Process to Enable IPv6

In general, here's how to enable IPv6 for a FastConnect virtual circuit:

  • Virtual circuit BGP: Ensure the FastConnect virtual circuit has IPv6 BGP addresses. If you're responsible for providing the BGP IP addresses, when you set up a new virtual circuit or edit an existing one, there's a place for the two IPv4 BGP addresses. There's a separate check box for Enable IPv6 Address Assignment and a place to provide the two IPv6 addresses. If you're editing an existing virtual circuit to add support for IPv6, it goes down while being reprovisioned to use the new BGP information.
  • VCN route tables: For each IPv6-enabled subnet in the VCN, update its route table to include rules that route the IPv6 traffic from the VCN to the IPv6 subnets in your on-premises network. For example, the Destination CIDR Block for a route rule would be an IPv6 subnet in your on-premises network, and the Target would be the dynamic routing gateway (DRG)  attached to the IPv6-enabled VCN.
  • VCN security rules: For each IPv6-enabled subnet in the VCN, update its security lists or relevant network security groups to allow IPv6 traffic between the VCN and your on-premises network. See Security Rules for IPv6 Traffic.

If you do not yet have a FastConnect connection, see these topics to get started:

Site-to-Site VPN and IPv6

If you use Site-to-Site VPN, you can configure it so that on-premises hosts with IPv6 addresses can communicate with an IPv6-enabled VCN. Here's how to enable IPv6 for the connection:

  • IPSec connection static routes: Configure the IPSec connection with the IPv6 static routes of your on-premises network.
  • VCN route tables: For each IPv6-enabled subnet in the VCN, update its route table to include rules that route the IPv6 traffic from the VCN to the IPv6 subnets in your on-premises network. For example, the Destination CIDR Block for a route rule would be an IPv6 static route for your on-premises network, and the Target would be the dynamic routing gateway (DRG)  attached to the IPv6-enabled VCN.
  • VCN security rules: For each IPv6-enabled subnet in the VCN, update its security lists or relevant network security groups to allow the wanted IPv6 traffic between the VCN and your on-premises network. See Security Rules for IPv6 Traffic.

If you have an existing Site-to-Site VPN IPSec connection that uses static routing, you can update the list of static routes to include ones for IPv6. Changing the list of static routes causes Site-to-Site VPN to go down while being reprovisioned. See Changing the Static Routes.

If you do not yet have Site-to-Site VPN, see these topics to get started:

DHCPv6

DHCPv6 auto-configuration of IP addresses is supported. You do not need to statically configure any IPv6 address.

DNS

The VCN's Internet Resolver supports IPv6, which means resources in your VCN can resolve IPv6 addresses of hosts outside the VCN. Assignment of a hostname to an IPv6 address is not supported.

Load Balancers

When you create a load balancer, you can choose to have an IPv4/IPv6 dual-stack configuration. When you choose the IPv6 option, the Load Balancer service assigns both an IPv4 and an IPv6 address to the load balancer. The load balancer receives client traffic sent to the assigned IPv6 address. The load balancer uses only IPv4 addresses to communicate with backend servers. IPv6 communication between the load balancer and the backend servers is not supported.

IPv6 address assignment occurs only at load balancer creation. You cannot assign an IPv6 address to an existing load balancer.

Comparison of IPv4 and IPv6 for Your VCN

The following table summarizes the differences between IPv4 and IPv6 addressing in a VCN.

Characteristic IPv4 IPv6
Addressing type supported IPv4 addressing is always required, regardless of whether IPv6 is enabled. IPv6 addressing is optional per VCN, optional per subnet in an IPv6-enabled VCN, and optional per VNIC in an IPv6-enabled subnet.
Supported traffic types IPv4 traffic is supported for all gateways. IPv4 traffic between instances within the VCN is supported (east/west traffic). IPv6 traffic is supported only with these gateways: internet gateway, local peering gateway, and DRG. Both inbound- and outbound-initiated IPv6 connections are supported between your VCN and the internet, and between your VCN and your on-premises network. IPv6 traffic between resources within a region (intra- and inter-VCN) is fully supported (east/west traffic). Also see Routing for IPv6 Traffic.
VCN size /16 to /30

Oracle GUA: /56 only

BYOIPv6: /64 or larger

ULA: /64 or larger

Subnet size /16 to /30, with 3 addresses reserved in each subnet by Oracle (first 2 and last 1). /64 only, with 8 addresses in the subnet reserved by Oracle (first 4 and last 4).
Private and public IP address space

Private: A VCN's private IPv4 CIDR can be from an RFC 1918 range or a publicly routable range (treated as private). You specify the range, unless you use the Console's VCN creation wizard, which always uses 10.0.0.0/16.

Public: The VCN does not have a dedicated public IPv4 address space. Oracle chooses any public addresses in your VCN.

Unlike with IPv4, your VCN can receive an allocated /56 GUA prefix from Oracle or import and assign a BYOIP prefix. Either of these can be internet routable if assigned to resources in public subnets. You also have an option to assign ULA addresses, which are not internet routable, regardless of whether the subnet is public or private.

IP address assignment

Private: Each VNIC gets a private IPv4 address. You can choose the address or let Oracle choose it.

Public: You determine whether the private IPv4 address has a public IP address associated with it (assuming the VNIC is in a public subnet). Oracle chooses the public IP address.

From an API standpoint: the PrivateIp object is separate from the PublicIp object. You can remove the public IP address from the private IPv4 address at any time.

You may assign IPv6 addresses from distinct prefixes to a VNIC if they are assigned to the subnet. You can choose the IPv6 address or let Oracle choose it.

From an API standpoint: IP addresses are included in the Ipv6 object and the distinction between public and private is controlled using the public/private subnet flag.

Internet access You control whether a subnet is public or private. You add or remove a public IP address from a private IPv4 address on a VNIC (assuming the VNIC is in a public subnet). You control whether a subnet is public or private. You do not add or remove a public IP address to or from the VNIC as you do with IPv4. Instead you enable or disable the internet access for all IPv6-enabled resources in the subnet using the public/private subnet flag.
Primary and secondary labels Each VNIC automatically has a primary private IP address, and you can assign up to 31 secondary private IPs per VNIC. You choose to add an IPv6 address to a VNIC, with no primary or secondary label. You can assign up to 32 IPv6s per VNIC.
Hostnames You can assign hostnames to IPv4 addresses. You cannot assign hostnames to IPv6 addresses.
Route rule limits See Service Limits. IPv4 and IPv6 route rules can reside together in the same route table. IPv6 route rules can target only an internet gateway, local peering gateway, or DRG. Limit on number of IPv6 route rules in a route table: 50.
Security rule limits See Service Limits. IPv4 and IPv6 security rules can reside together in same network security group or security list. IPv6 security rules can use only IPv6 prefix ranges for source or destination, and not a service prefix label used for a service gateway. Limit on number of IPv6 security rules in a security list: 50 ingress and 50 egress. Limit on number of IPv6 security rules in a network security group: 16 total.
Reserved public IP addresses Supported. Not supported.
Regional or AD-specific Primary private IPv4 addresses are AD -specific. Secondary private IPv4 addresses are AD-specific unless assigned to a VNIC in a regional subnet. Public IP addresses can be AD-specific or regional depending on the type (ephemeral or reserved). See Public IP Addresses. IPv6 addresses are regional.

Setting Up an IPv6-Enabled VCN with Internet Access

Use the following process to set up an IPv6-enabled VCN with internet access so you can easily create an instance and connect to it by using its globally routable IPv6 address.

Task 1: Create the IPv6-enabled VCN
  1. Open the navigation menu, click Networking, and then click Virtual Cloud Networks.
  2. Choose a compartment you have permission to work in (on the left side of the page). The page updates to display only the resources in that compartment. If you're not sure which compartment to use, contact an administrator. For more information, see Access Control.
  3. Click Create Virtual Cloud Network.
  4. Enter the following:

    • Name: A descriptive name for the VCN. It doesn't have to be unique, and it cannot be changed later in the Console (but you can change it with the API). Avoid entering confidential information.
    • Create in Compartment: Leave as is.
    • CIDR Block: A single, contiguous IPv4 CIDR block for the VCN. For example: 172.16.0.0/16. You cannot change this value later. See Allowed VCN Size and Address Ranges. For reference, here's a CIDR calculator.
    • Enable IPv6 Address Assignment: Oracle can allocate an IPv6 prefix for you, you can select a BYOIPv6 prefix you have already imported, or you can specify a ULA prefix. You cannot later disable IPv6 for the VCN but you can change the IPv6 prefix or prefixes on the VCN as long as there is always at least one IPv6 prefix. If you accept an Oracle-allocated IPv6 prefix, you receive a /56. For BYOIPv6 or ULA, specify any prefix size of /64 or larger. All IPv6-enabled subnets are /64 in size.
    • Use DNS Hostnames in this VCN (supported for IPv4 only): Required for assignment of DNS hostnames to hosts in the VCN, and required if you plan to use the VCN's default DNS feature (called the Internet and VCN Resolver). If the check box is selected, you can specify a DNS label for the VCN, or allow the Console to generate one for you. The dialog box automatically displays the corresponding DNS Domain Name for the VCN (<VCN DNS label>.oraclevcn.com). For more information, see DNS in Your Virtual Cloud Network.
    • Tags: Leave as is. You can add tags later. For more information, see Resource Tags.
  5. Click Create Virtual Cloud Network.

    The VCN is then created and displayed on the Virtual Cloud Networks page in the compartment you chose.

Task 2: Create a regional IPv6-enabled public subnet
  1. While still viewing the VCN, click Create Subnet.
  2. Enter the following:

    • Name: A descriptive name for the subnet (for example, Regional Public Subnet). It doesn't have to be unique, and you can change it later. Avoid entering confidential information.
    • Regional or Availability Domain-specific subnet: Oracle recommends creating only regional subnets, which means that the subnet can contain resources in any of the region's availability domains. If you instead choose Availability Domain-Specific, you must also specify an availability domain. This choice means that any instances or other resources later created in this subnet must also be in that availability domain.
    • CIDR Block: A single, contiguous IPv4 CIDR block for the subnet (for example, 172.16.0.0/24). The address block must be within the VCN's IPv4 CIDR block and not overlap any other subnets. You cannot change this value later. See Allowed VCN Size and Address Ranges. For reference, here's a CIDR calculator.
    • Enable IPv6 Address Assignment: You can add and remove prefixes to an IPv6-enabled subnet. However, at least one IPv6 prefix must always remain after IPv6 has been enabled. An IPv6 enabled subnet cannot become an IPv4-only subnet. The subnet can only have one IPv6 prefix. All IPv6 enabled subnets are always /64 in size. If you previously assigned several IPv6 prefixes to the VCN that contains this subnet, you can choose which prefix you assign to the subnet.
      • If you have an Oracle-allocated prefix assigned to the VCN, select the check box and enter two hexadecimal characters (00-FF).
      • If you assigned a BYOIPv6 or ULA prefix in the VCN, select it and specify hex characters to assign a /64 to the subnet.
      For more information about the IPv6 address format, see Overview of IPv6 Addresses.
    • Route Table: Select the default route table.
    • Private or public subnet: Select Public Subnet, which means instances in the subnet can optionally have public IPv4 addresses. Internet communication using IPv6 is allowed when GUA IPv6 addresses are assigned to resources hosted in a public subnet. For more information, see Access to the Internet.
    • Use DNS Hostnames in this Subnet (supported for IPv4 only): This option is available only if you provided a DNS label for the VCN during creation. The option is required for assignment of DNS hostnames to hosts in the subnet, and also when you plan to use the VCN's default DNS feature (called the Internet and VCN Resolver). If the check box is selected, you can specify a DNS label for the subnet, or let the Console generate one for you. The dialog box automatically displays the corresponding DNS Domain Name for the subnet (<subnet_DNS_label>.<VCN_DNS_label>.oraclevcn.com). For more information, see DNS in Your Virtual Cloud Network.
    • DHCP Options: Select the default set of DHCP options.
    • Security Lists: Select the default security list.
    • Tags: Leave as is. You can add tags later if you want. For more information, see Resource Tags.
  3. Click Create Subnet.

    The subnet is then created and displayed on the Subnets page.

Task 3: Create the internet gateway
  1. Under Resources, click Internet Gateways.
  2. Click Create Internet Gateway.
  3. Enter the following:

    • Name: A descriptive name for the internet gateway. It doesn't have to be unique, and it cannot be changed later in the Console (but you can change it with the API). Avoid entering confidential information.
    • Create in Compartment: Leave as is.
    • Tags: Leave as is. You can add tags later. For more information, see Resource Tags.
  4. Click Create Internet Gateway.

    Your internet gateway is created and displayed on the Internet Gateways page. The internet gateway is already enabled, but you must add route rules that allow IPv4 and IPv6 traffic.

Task 4: Update the default route table to use the internet gateway

The default route table starts out with no rules. Here you add rules that route all IPv4 and IPv6 traffic destined for addresses outside the VCN to the internet gateway. The existence of these rules also enables inbound connections to come from the internet to the subnet, through the internet gateway. You use security rules to control the types of traffic that are allowed in and out of the instances in the subnet (see the next task).

No route rule is required to route traffic within the VCN.

  1. Under Resources, click Route Tables.
  2. Click the default route table to view its details.
  3. Click Add Route Rules.
  4. Enter the following:

    • Target Type: Internet Gateway
    • Destination CIDR block: 0.0.0.0/0 (which means that all IPv4 non-intra-VCN traffic that is not already covered by other rules in the route table goes to the target specified in this rule).
    • Compartment: The compartment where the internet gateway is located.
    • Target: The internet gateway you created.
    • Description: An optional description of the rule.
  5. Click + Additional Route Rule.
  6. Enter the following:

    • Target Type: Internet Gateway
    • Destination CIDR block: ::/0 (for the IPv6 traffic).
    • Compartment: The compartment where the internet gateway is located.
    • Target: The internet gateway you created.
    • Description: An optional description of the rule.
  7. Click Add Route Rules.

The default route table now has two rules for the internet gateway, one for IPv4 traffic and one for IPv6 traffic. Because the subnet was set up to use the default route table, the resources in the subnet can now use the internet gateway. The next step is to specify the types of traffic you want to allow in and out of the instances you later create in the subnet.

Task 5: Update the default security list (optional)
Note

This task is about configuring security rules to allow traffic to and from your instances. Although this task uses a security list to implement those rules, you can also use network security groups to implement security rules.

Earlier you set up the subnet to use the VCN's default security list. This list already includes basic rules that allow essential IPv4 and IPv6 traffic. In this task, you add any additional security rules that allow the types of connections that the instances in the VCN need.

For example: in a public subnet with an internet gateway, the instances you create might need to receive inbound HTTPS connections from the internet (if they are web servers). Here's how to add another rule to the default security list to enable that traffic:

  1. Under Resources, click Security Lists.
  2. Click the default security list to view its details. By default, you land on the Ingress Rules page.
  3. Click Add Ingress Rule.
  4. To enable inbound connections for HTTPS (TCP port 443), enter the following:

    • Stateless: Unselected (this is a stateful rule)
    • Source Type: CIDR
    • Source CIDR: 0.0.0.0/0 (or ::/0 if you want to enable IPv6 traffic with this rule)
    • IP Protocol: TCP
    • Source Port Range: All
    • Destination Port Range: 443
    • Description: An optional description of the rule.
  5. Click Add Ingress Rule.
Important

Security List Rule for Windows Instances

If you're going to create Windows instances, you need to add a security rule to enable Remote Desktop Protocol (RDP) access. Specifically, you need a stateful ingress rule for TCP traffic on destination port 3389 from source 0.0.0.0/0 (and a separate rule with ::/0 for IPv6 traffic) and any source port. For more information, see Security Rules.

For a production VCN, you typically set up one or more custom security lists for each subnet. If you like, you can edit the subnet to use different security lists. If you choose not to use the default security list, do so only after carefully assessing which of its default rules you want to duplicate in your custom security list. For example: the default ICMP rules in the default security list are important for receiving connectivity messages for IPv4.

Task 6: Create an instance

Your next step is to create an instance in the subnet. When you create the instance, you choose the availability domain , which VCN and subnet to use, and several other characteristics.

Each instance automatically gets a private IPv4 address. When you create an instance in a public subnet, you choose whether the instance gets a public IPv4 address. A public IPv4 address is NOT required for globally routable IPv6 traffic. But if you want to connect to the instance from an IPv4 host, you must give the instance a public IP address, or else you can't access them through the internet gateway. The default (for a public subnet) is for the instance to get a public IP address.

For more information and instructions, see Launching an Instance.

Task 7: Add an IPv6 address to the instance
  1. While viewing the instance you created in the previous step, click Attached VNICs.
  2. Click the name of the primary VNIC from the list of attached VNICs.
  3. Under Resources, click IPv6 Addresses.
  4. Click Assign IPv6 Address.
  5. Enter the following:

    • Prefix: Select a prefix from which the IPv6 address is automatically assigned. Available choices depend on what you choose in IPv6 address assignment:
      • Automatically assign IPv6 addresses from prefix: Choose this option to let the console select an address from the IPv6 prefix assigned to this subnet.
      • Manually assign IPv6 addresses from prefix: Choose this option to select a specific address from the IPv6 prefix assigned to this subnet.
        • Unassign if already assigned to another VNIC: (This option is only available if you select Manually assign IPv6 addresses from prefix:) Leave this check box as is (cleared). Only use this option to force reassignment of an IPv6 address that is already assigned to another VNIC in the subnet.
    • Tags: Leave as is. You can add tags later. For more information, see Resource Tags.
  6. Click Assign.

    The IPv6 is created and then displayed on the IPv6 Addresses page for the VNIC.

Task 8: Configure the instance's OS to use IPv6

You must configure the instance's OS to use the IPv6. For more information, see Configuring an Instance OS to use IPv6.

Assign the IPv6 address dynamically when using Oracle Linux 8. Enabling IPv6 during the compute create is not supported, so you might not see the IPv6 address immediately after the instance is launched. After the compute instance is up, you can wait for the next DHCPv6 cycle to get the IPv6 address, or you can use the DHCPv6 client service to manually cycle DHCP and update with the newly added IPv6 address. To use the DHCPv6 client, enter:

sudo dhclient -6 ens3
Note

You might want to use the following command to allow the DHCPv6 client service from the firewall-cmd daemon on the virtual machine:
sudo firewall-cmd --add-service=dhcpv6-client 

Managing IPv6s in the Console

This section includes basic tasks for working with IPv6-related resources.

To create an IPv6-enabled VCN
Important

After enabling IPv6 for a VCN, you cannot disable it.

See the instructions in Task 1: Create the IPv6-enabled VCN.

To create an IPv6-enabled subnet
Important

After enabling IPv6 for a subnet, you cannot disable it.

Summary: Creating an IPv6-enabled subnet is similar to creating an IPv4 subnet. The difference is that you must select which VCN IPv6 prefix you want to assign a /64 from and specify characters accordingly. If selecting the check box for an Oracle-allocated prefix, you can provide 8 bits for the subnet's portion of the IPv6 prefix. See Overview of IPv6 Addresses.

For general instructions, see Task 2: Create a regional IPv6-enabled public subnet. If you want a private subnet, select the radio button for Private Subnet when creating the subnet.

To assign an IPv6 to a VNIC

The process for adding an IPv6 to a VNIC is similar to adding a secondary private IPv4 address. You can specify the particular IPv6 address to use or let Oracle choose it from the subnet. For more information, see Overview of IPv6 Addresses. After assigning the IPv6 to the VNIC, you must configure the OS to use the IPv6.

  1. Assign the IPv6. For general instructions, see Task 7: Add an IPv6 address to the instance.
  2. Configure the OS to use the IPv6 address. For more information, see Configuring an Instance OS to use IPv6.
To move an IPv6 to another VNIC in the subnet

The process is similar to moving a secondary private IPv4 address from one VNIC to another (let's call them the original VNIC and the new VNIC). You assign the IPv6 to the new VNIC, specify the IPv6 address, and select the check box for Unassign if already assigned to another VNIC. Oracle automatically unassigns it from original VNIC and assigns it to the new VNIC.

  1. Confirm you're viewing the compartment that contains the instance you're interested in.
  2. Open the navigation menu and click Compute. Under Compute, click Instances.
  3. Click the instance to view its details.
  4. Under Resources, click Attached VNICs.

    The primary VNIC and any secondary VNICs attached to the instance are displayed.

  5. Click the VNIC you're interested in.
  6. Under Resources, click IPv6 Addresses.
  7. Click Assign Private IP Address.
  8. Enter the following:

    • IPv6 Address: The IPv6 address that you want to move.
    • Unassign if already assigned to another VNIC: Select this check box to move the IPv6 address from the currently assigned VNIC.
    • Tags: If you have permissions to create a resource, then you also have permissions to apply free-form tags to that resource. To apply a defined tag, you must have permissions to use the tag namespace. For more information about tagging, see Resource Tags. If you are not sure whether to apply tags, skip this option (you can apply tags later) or ask your administrator.
  9. Click Assign.

The IP address is moved from the original VNIC to the new VNIC.

To delete an IPv6 from a VNIC
  1. Confirm you're viewing the compartment that contains the instance you're interested in.
  2. Open the navigation menu and click Compute. Under Compute, click Instances.
  3. Click the instance to view its details.
  4. Under Resources, click Attached VNICs.

    The primary VNIC and any secondary VNICs attached to the instance are displayed.

  5. Click the VNIC you're interested in.
  6. Under Resources, click IPv6 Addresses.
  7. For the IPv6 you want to delete, click the Actions menu, and then click Delete IPv6.
  8. Confirm when prompted.

The IPv6 address is returned to the pool of available addresses in the subnet.

Configuring an Instance OS to use IPv6

After assigning an IPv6 to the VNIC through the Console, an instance needs an assigned address. DHCPv6 will automatically assign the instance an IPv6 address, which might require you to wait for the next refresh cycle. You can also require the instance's operating system to immediately refresh its IPv6 address.

Oracle Linux Configuration

Oracle Linux 8 uses the following command to refresh an IPv6 address on an instance:

sudo dhclient -6 <interface>
Note

If you want to use the DHCLIENT service in Oracle Linux 8, you might first have to run this command:
sudo firewall-cmd --add-service=dhcpv6-client 

If you haven't yet, ensure that the VCN's route table and security rules are configured for the wanted IPv6 traffic. See Routing for IPv6 Traffic and Security Rules for IPv6 Traffic.

Windows Configuration

You can use the following Windows command line or the Network Connections UI to ask the instance to refresh the IPv6 address:

ipconfig /renew6
Command Line

If you use PowerShell, you must run it as an administrator. The following configuration persists through a reboot of the instance. Apply it as soon as possible after the instance is created.

Run the following command:


ipconfig /renew6.

If you haven't yet, ensure that the VCN's route table and security rules are configured for the wanted IPv6 traffic. See Routing for IPv6 Traffic and Security Rules for IPv6 Traffic.