Create an IPSec Tunnel between a VDC and On-Premises Gateway
Introduction
This tutorial demonstrates configuring an IPSec site-to-site VPN Gateway for secure and encrypted communications, establishing a connection between an IONOS Cloud VDC and a simulated user-managed on-premises installation. It utilizes a managed VPN Gateway in the IONOS Cloud and a user-managed on-premises gateway.
Overview
This tutorial demonstrates the use of the following:
Components
Description
Two VDCs
- ionos-cloud-txl as IONOS's VDC.
- user-on-prem-lhr simulates a user-managed on-premises setup.
Managed gateways
We use a single managed gateway in ionos-cloud-txl for the cloud side.
For a user-managed gateway, we use on-premises simulation, install the components, and manually configure IPSec on a virtual server to complete the setup.
Before you begin
The following information is necessary to set up an IPSec connection between a VDC and on-premises VDC:
Components
IONOS Cloud (Left) ionos-cloud-txl
User On-Premises (Right) user-on-prem-lhr
VDC Name
ionos-cloud-txl
user-on-prem-lhr
Gateway Public Address
203.0.113.10
203.0.113.20
LAN ID
1
Not applicable
LAN Subnet
192.168.1.0/24
192.168.2.0/24
Gateway LAN Address
192.168.1.5
192.168.2.5
LAN Host 1
192.168.1.11
192.168.2.11
LAN Host 2
192.168.1.12
192.168.2.12
Pre-Shared Key
Remember to use the appropriate key.
Example: vPabcdefg123435hij565k7lmno8pq=. This is a sample key used as an example in this document. Do not use this key for real-world scenarios.
Reserve IP addresses
Before proceeding, ensure you have an IP block with at least one free IP address to assign to each gateway. For more information, see Reserve an IPv4 Address.
IONOS Cloud (Left) ionos-cloud-txl Gateway Public Address
User On-Premises (Right) user-on-prem-lhr Gateway Public Address
203.0.113.10
203.0.113.20
Configure LAN
This tutorial uses 192.168.1.0/24 and 192.168.2.0/24 for private LANs in IONOS Cloud (Left) ionos-cloud-txl and User On-Premises (Right) user-on-prem-lhr respectively. Remember to assign an IP address from the subnet to each gateway. The chosen IP address must be outside the DHCP pool and range from .2 - .9.
Components
IONOS Cloud (Left) ionos-cloud-txl
User On-Premises (Right) user-on-prem-lhr
LAN ID
1
Not applicable
LAN Subnet
192.168.1.0/24
192.168.2.0/24
Gateway LAN Address
192.168.1.5
192.168.2.5
Generate Pre-Shared Key (PSK)
Our current IPSec implementation supports PSK (which is expected to support certificates in the future). When provisioning gateways, ensure you generate a PSK at least 32 characters long. Optionally, you can also generate a PSK while creating an IPSec tunnel. The following commands explain how to generate PSK for Linux and Windows, respectively:
Execute either of these commands:
openssl rand -base64 48 head -c 32 /dev/urandom | base64$b = New-Object byte[] 32; (New-Object System.Security.Cryptography.RNGCryptoServiceProvider).GetBytes($b); [System.Convert]::ToBase64String($b) | Set-Content -Path .\psk.txt -Encoding ASCII Execution
The execution process is divided into the following steps:
1. Simulate IONOS Cloud 2. Simulate on-premises setup 3. Provision the VPN Gateway 4. Configure the VPN tunnel 5. Deploy on-premises IPSec instance 6. Configure routing on LAN hosts
1. Simulate IONOS Cloud ionos-cloud-txl
ionos-cloud-txlBelow are some screenshots from the DCD that contains the required VDCs.
To begin with, two virtual servers on the IONOS Cloud are provisioned and connected to each other via a private LAN. In this instance, LAN1 uses a custom subnet of 192.168.1.0/24. We designate these two servers as 192.168.1.11 and 192.168.1.12, respectively.
2. Simulate on-premises user-on-prem-lhr setup
user-on-prem-lhr setupImagine the user-on-prem-lhr VDC as a user-managed site where you provision three virtual servers. Here, we will use the LAN subnet 192.168.2.0/24. The Users VPN GW has been configured with internet access IP address: 203.0.113.20 and a private LAN address of 192.168.2.5, this will function as the on-premises host acting as a user-managed gateway. The two private LAN hosts are addressed as 192.168.2.11 and 192.168.2.12, respectively.
3. Provision the VPN Gateway
1. In the DCD, go to Menu > Network Services > VPN Gateway.
2. Click Create VPN Gateway from the VPN Gateways window.
3. Enter the following details:
Components
Description
Example
Name
Enter a descriptive name for the gateway instance. It is not required to be globally unique but must be limited to 255 characters.
site_to_site
Description
Enter a descriptive text for the gateway. It is limited to 1024 characters.
VPN Gateway for creating an IPSec Tunnel between a VDC and on-premises gateway.
Location
Select a location from the drop-down list of available locations for VPN Gateway.
de/txl
IP Address
Select an IP address from the drop-down list of available public IPv4 addresses.
203.0.113.10
The Enhanced VPN tier is selected by default. The number of LANs and tunnels or peers differ for each tier. You can also enable High Availability for a chosen tier, allowing VMs to operate in an active-passive mode. It minimizes downtime during a failover and ensures an uninterrupted connection.
The IPSec protocol is selected by default, and no additional configuration parameters are necessary.
Attach a VPN Gateway to LANs in ionos-cloud-txl. You can only connect to LANs in the exact location where the VPN Gateway was provisioned. Take a look at the following mandatory parameters:
Components
Description
Example
Datacenter
Select a data center from the drop-down that lists VDCs in the same location as the gateway.
ionos-cloud-txl
Connections
A list of connected LANs and the LAN addresses.
Refer to the following table.
After selecting a data center, click Add LAN Connection to launch an additional pop-up window to set the following properties:
Components
Description
Example
LAN
The ID of the LAN to connect to.
1
IPv4 CIDR
The LAN IPv4 address assigned to the subnet's gateway in CIDR notation.
192.168.1.5
IPv6 CIDR
The LAN IPv6 address assigned to the subnet's gateway in CIDR notation.
Not applicable
Define a maintenance window to begin at the specified start time (UTC) and continue for a duration of four hours. Specify the following:
Components
Description
Example
Day
Select a day from the drop-down list to set a day for maintenance.
Sunday
Time
Enter a time using the pre-defined format (hh:mm:ss) to schedule the maintenance task.
01:40 AM
4. Click Save and wait for the gateway to complete provisioning. The process typically takes about 8-10 minutes, but further operations on the gateway will be instantaneous.
4. Configure the VPN tunnel
Now that the VPN Gateway instance is provisioned, the next step is to configure a tunnel to permit the two sides to talk to each other. We will need to configure a tunnel on both gateways, but the on-premises will be configured using IPSec configuration files.
1. Click Create Tunnels to begin configuring a new tunnel.
Enter the following details to configure a tunnel:
Components
Description
Example
Tunnel Name
Specify a name for the tunnel. It does not need to be globally unique and can be up to 255 characters long.
customer_site
Description
Enter more descriptive text for the peer, not exceeding 1024 characters.
Not applicable
Remote Host
The public IPv4 address of the remote VPN Gateway.
203.0.113.20
Set the PSK as shown:
Components
Description
Example
Pre-Shared Key
Enter a strong key that is at least 32 characters long.
vPabcdefg123435hij565k7lmno8pq=
Here, you can set the various encryption and integrity algorithms, Diffie-Hellman Group, and lifetimes for the IKE exchange phase. For demonstration, the available options are aligned with BSI best practices. However, we will accept the default selections.
Components
Description
Example
Diffe-Hellman
The Diffie-Hellman (DH) key exchange algorithm makes a shared encryption key available to two entities without exchanging the key. The shared encryption key serves as a symmetric key for encrypting data. Only the two parties involved in the DH key exchange can derive the shared key, which is never transmitted over the network.
15-MODP3072
Encryption Algorithm
Encryption algorithms safeguard data to prevent third-party access during transmission.
AES128-CTR
Integrity Algorithm
Integrity algorithms verify messages and randomness, ensuring packets are authentic and not altered by a third party before arrival, and generate keying material for encryption.
SHA256
Lifetime
The duration (in seconds) for which a negotiated IKE SA key remains valid. Before the key lifetime expires, the SA must be re-keyed; otherwise, upon expiration, the SA must begin a new IKEv2 IKE SA re-key.
86400
Here, you can set the various encryption and integrity algorithms, Diffie-Hellman Group, and lifetimes for the ESP phase. For demonstration, the available options are aligned with BSI best practices. However, we will accept the default selections.
Components
Description
Example
Diffe-Hellman
The Diffie-Hellman (DH) key exchange algorithm is a method used to make a shared encryption key available to two entities without exchanging the key. The encryption key for the two devices is used as a symmetric key for encrypting data. Only the two parties involved in the DH key exchange can deduce the shared key, and the key is never sent over the wire.
15-MODP3072
Encryption Algorithm
Encryption algorithms safeguard data to prevent third-party access during transmission.
AES128-CTR
Integrity Algorithm
Integrity algorithms verify messages and randomness, ensuring packets are authentic and not altered by a third party before arrival, and generate keying material for encryption.
SHA256
Lifetime
The ESP SA specifies the duration for which keys generated during the IKE negotiation remain valid for encrypting and authenticating the data packets being transmitted.
3600
Configure the subnets in CIDR format, which are permitted to connect to the tunnel.
Components
Description
Example
Cloud Network CIDRs
Network addresses on the cloud side that are permitted to connect to the tunnel.
192.168.1.0/24
Peer Network CIDRs
Network addresses on the peer or remote side that are permitted to connect to the tunnel.
192.168.2.0/24
2. Click Save to save the tunnel configuration. This operation usually takes about one to two minutes to complete.
5. Deploy on-premises IPSec instance
In this tutorial, Users VPN GW in user-on-prem-lhr acts as a user-managed gateway. It has internet access, so SSH can be used instead of the web console. Start establishing an SSH connection to Users VPN GW's public IPv4 address in London, remember to forward your ssh key when establishing this session. You will need this key while establishing a console session to the LAN hosts.
6. Configure routing on LAN hosts
Currently, it is impossible to automate the addition of routes to LAN hosts to route the required subnets over the VPN Gateway. In this section, we will manually add the required routes. Remember to add them to the LAN hosts in both the VDCs.
6.1 Configure routing for IONOS Cloud LAN hosts ionos-cloud-txl
ionos-cloud-txl6.2 Set persistent routes
In the 6.1 Configure routing for IONOS Cloud LAN hosts ionos-cloud-txl section, we added routes that will not persist during a reboot. You must determine how to set persistent routes for your choice of operating system.
6.3 Configure routing for on-premises LAN hosts user-on-prem-lhr
user-on-prem-lhrVerify connectivity
You should now be able to ping hosts in the simulated on-premises setup in user-on-prem-lhr from cloud hosts in ionos-cloud-txl and vice-versa.
root@lanhost1:~# ping -c 5 192.168.2.12
PING 192.168.2.12 (192.168.2.12) 56(84) bytes of data.
64 bytes from 192.168.2.12 icmp_seq=1 ttl=62 time=18.8 ms
64 bytes from 192.168.2.12 icmp_seq=2 ttl=62 time=19.3 ms
64 bytes from 192.168.2.12 icmp_seq=3 ttl=62 time=19.0 ms
64 bytes from 192.168.2.12 icmp_seq=4 ttl=62 time=18.8 ms
64 bytes from 192.168.2.12 icmp_seq=5 ttl=62 time=19.1 ms
--- 192.168.2.12 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4005ms
rtt min/avg/max/mdev = 18.782/18.995/19.270/0.188 ms
root@lanhost1:~# root@lanhost1:~# ping -c 5 192.168.1.12
PING 192.168.1.12 (192.168.1.12) 56(84) bytes of data.
64 bytes from 192.168.1.12 icmp_seq=1 ttl=62 time=18.8 ms
64 bytes from 192.168.1.12 icmp_seq=2 ttl=62 time=19.3 ms
64 bytes from 192.168.1.12 icmp_seq=3 ttl=62 time=19.0 ms
64 bytes from 192.168.1.12 icmp_seq=4 ttl=62 time=18.8 ms
64 bytes from 192.168.1.12 icmp_seq=5 ttl=62 time=19.1 ms
--- 192.168.1.12 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4006ms
rtt min/avg/max/mdev = 18.999/19.594/21.062/0.751 ms
root@lanhost1:~#Summary
You have successfully configured a site-to-site VPN between the IONOS Cloud ionos-cloud-txl and a user-managed on-premises setup user-on-prem-lhr by utilizing a managed VPN Gateway in the cloud and a user-managed on-premises gateway.
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