VPN as a Service

Overview

VPN as a Service (VPNaaS) provides IPsec-based site-to-site tunnel connectivity, enabling secure communication between your Polystack private cloud and remote data centers, branch offices, or other cloud environments. VPNaaS is available with Polystack deployments.

Prerequisites

Active project with member role or higher
At least one router with an external gateway configured
Remote site VPN endpoint details (peer IP, subnets, pre-shared key)
VPNaaS enabled by your administrator (enable_neutron_vpnaas: "yes")

Key Concepts

Concept	Description
IKE Policy	Defines the Internet Key Exchange parameters used during Phase 1 negotiation — authentication algorithm, encryption algorithm, IKE version (v1 or v2), and key lifetime
IPsec Policy	Defines the Phase 2 parameters for the data channel — encryption algorithm, authentication algorithm, encapsulation mode (tunnel or transport), and Perfect Forward Secrecy (PFS) group
VPN Service	Associates a VPN with a specific router and subnet in your project
Endpoint Group	Defines the local or remote subnets that participate in the VPN tunnel
IPsec Site Connection	Combines the IKE policy, IPsec policy, VPN service, and endpoint groups into an active tunnel to a remote peer

Supported Algorithms

IKE Policy
IPsec Policy

Parameter	Supported Values	Default
IKE Version	v1, v2	v1
Auth Algorithm	sha1, sha256, sha384, sha512	sha1
Encryption Algorithm	aes-128, aes-192, aes-256, 3des	aes-128
Phase 1 Negotiation Mode	main	main
Lifetime Value	60 — 86400 seconds	3600
PFS	group2, group5, group14	group5

Use IKEv2 with AES-256 and SHA-256 for production deployments. IKEv1 is supported for backward compatibility with legacy equipment.

Parameter	Supported Values	Default
Transform Protocol	esp, ah, ah-esp	esp
Auth Algorithm	sha1, sha256, sha384, sha512	sha1
Encryption Algorithm	aes-128, aes-192, aes-256, 3des	aes-128
Encapsulation Mode	tunnel, transport	tunnel
PFS	group2, group5, group14	group5
Lifetime Value	60 — 86400 seconds	3600

Enable Perfect Forward Secrecy (PFS) with at least group14 (2048-bit DH) for production tunnels.

Create a VPN Connection

Dashboard
CLI

Create an IKE Policy

Navigate to Network > VPNs (IKE Policies tab) and click Create.

Field	Value
Name	A descriptive name (e.g., `ike-aes256-sha256`)
IKE Version	v2
Encryption Algorithm	aes-256
Auth Algorithm	sha256
PFS	group14
Lifetime Value	3600

Create an IPsec Policy

Navigate to Network > VPNs (IPsec Policies tab) and click Create.

Field	Value
Name	A descriptive name (e.g., `ipsec-aes256-sha256`)
Transform Protocol	esp
Encryption Algorithm	aes-256
Auth Algorithm	sha256
Encapsulation Mode	tunnel
PFS	group14

Create a VPN Gateway

Navigate to Network > VPNs (VPN Gateways tab) and click Create.

Field	Value
Name	A descriptive name (e.g., `vpn-to-branch-office`)
Router	Select the router with an external gateway
Subnet	Select the local subnet to expose through the tunnel

Create Endpoint Groups

Navigate to Network > VPNs (VPN EndPoint Groups tab) and create two endpoint groups:Local Endpoint Group:

Field	Value
Name	`local-subnets`
Type	subnet
Endpoints	Select your local project subnet(s)

Remote Endpoint Group:

Field	Value
Name	`remote-subnets`
Type	cidr
Endpoints	Enter the remote subnet CIDRs (e.g., `192.168.1.0/24`)

Create the IPsec Site Connection

Navigate to Network > VPNs (IPsec Site Connections tab) and click Create.

Field	Value
Name	`connection-to-branch`
VPN Service	Select the VPN service created above
IKE Policy	Select the IKE policy created above
IPsec Policy	Select the IPsec policy created above
Local Endpoint Group	`local-subnets`
Peer Endpoint Group	`remote-subnets`
Peer Gateway Public Address	Public IP of the remote VPN device
Peer ID	Remote peer identifier (typically the peer gateway IP)
Pre-Shared Key(PSK) String	Shared secret agreed upon with the remote site

Click Create to establish the tunnel.

The connection appears in the list with status Active once both sides negotiate successfully.

Create an IKE Policy

Create IKE policy

openstack vpn ike policy create ike-aes256-sha256 \
  --ike-version v2 \
  --auth-algorithm sha256 \
  --encryption-algorithm aes-256 \
  --pfs group14 \
  --lifetime units=seconds,value=3600

Create an IPsec Policy

Create IPsec policy

openstack vpn ipsec policy create ipsec-aes256-sha256 \
  --transform-protocol esp \
  --auth-algorithm sha256 \
  --encryption-algorithm aes-256 \
  --pfs group14 \
  --encapsulation-mode tunnel

Create a VPN Service

Create VPN service

openstack vpn service create vpn-to-branch-office \
  --router my-router \
  --subnet my-local-subnet

Create Endpoint Groups

Create local endpoint group

openstack vpn endpoint group create local-subnets \
  --type subnet \
  --value my-local-subnet

Create remote endpoint group

openstack vpn endpoint group create remote-subnets \
  --type cidr \
  --value 192.168.1.0/24

Create the IPsec Site Connection

Create IPsec site connection

openstack vpn ipsec site connection create connection-to-branch \
  --vpnservice vpn-to-branch-office \
  --ikepolicy ike-aes256-sha256 \
  --ipsecpolicy ipsec-aes256-sha256 \
  --local-endpoint-group local-subnets \
  --peer-endpoint-group remote-subnets \
  --peer-address 203.0.113.50 \
  --peer-id 203.0.113.50 \
  --psk "your-pre-shared-key"

Validation

Confirm the VPN tunnel is established and operational:

Dashboard
CLI

Navigate to Network > VPNs (IPsec Site Connections tab). The connection status should display Active.

Status	Meaning
Active	Tunnel is established and passing traffic
Down	Tunnel negotiation failed or peer is unreachable
Pending Create	Connection is being provisioned
Error	Configuration error — review IKE/IPsec parameters

Connection status is Active — the tunnel is operational.

Check connection status

openstack vpn ipsec site connection show connection-to-branch -c status -c id

Expected output:

Expected response

+--------+--------------------------------------+
| Field  | Value                                |
+--------+--------------------------------------+
| id     | a1b2c3d4-e5f6-7890-abcd-ef1234567890 |
| status | ACTIVE                               |
+--------+--------------------------------------+

Status shows ACTIVE — the VPN tunnel is operational.

Troubleshooting

Connection stuck in DOWN status

Cause: The remote peer is unreachable or IKE/IPsec parameters do not match.Resolution:

Verify the peer gateway IP is reachable from the router’s external network
Confirm that IKE version, encryption, authentication, and PFS settings match on both sides
Check that the pre-shared key is identical on both endpoints
Verify security group rules allow UDP ports 500 and 4500 (IKE/NAT-T) and IP protocol 50 (ESP)

Tunnel established but no traffic flows

Cause: Endpoint group CIDRs do not match between the local and remote configurations.Resolution:

Verify the local endpoint group subnets match what the remote side expects as “remote” subnets
Verify the remote endpoint group CIDRs match the actual subnets behind the remote peer
Check routing tables on both sides to ensure traffic is directed through the tunnel

Next Steps

Security Groups

Configure firewall rules to control traffic flow through the VPN tunnel

Routers

Manage the routers that anchor your VPN services

Network Topology

Visualize your network layout including VPN connections

Key Manager

Store and manage VPN pre-shared keys and certificates securely

Core Services

Other Services

Overview

Key Concepts

Supported Algorithms

Create a VPN Connection

Create an IKE Policy

Create an IPsec Policy

Create a VPN Gateway

Create Endpoint Groups

Create the IPsec Site Connection

Create an IKE Policy

Create an IPsec Policy

Create a VPN Service

Create Endpoint Groups

Create the IPsec Site Connection

Validation

Troubleshooting

Next Steps

Security Groups

Routers

Network Topology

Key Manager

​Overview

​Key Concepts

​Supported Algorithms

​Create a VPN Connection

Create an IKE Policy

Create an IPsec Policy

Create a VPN Gateway

Create Endpoint Groups

Create the IPsec Site Connection

Create an IKE Policy

Create an IPsec Policy

Create a VPN Service

Create Endpoint Groups

Create the IPsec Site Connection

​Validation

​Troubleshooting

​Next Steps

Security Groups

Routers

Network Topology

Key Manager

Overview

Key Concepts

Supported Algorithms

Create a VPN Connection

Validation

Troubleshooting

Next Steps