This tutorial will explain how to setup and configure a DDoS protected OpenVPN server. This guide assumes you know how to setup an OpenVPN server or already have a server running (and you have access to it).
This guide does not cover providing DDoS protection via OpenVPN. We provide DDoS Protection via GRE and IP-ip-IP on Linux and Windows. As we feek this a superior and more reliable solution at this time we do not offer OpenVPN as a backend connection option.
Step 1: Backend Setup
Setup your OpenVPN on your server, this server will be from here on referred to as the "backend server". On the backend server you may use whichever Operating System you are most familiar with, however if unsure we recommend Debian Linux.
Please ensure that the service is running and connectable on the backend server.
Step 2: Purchase DDoS Protection Service
Choose a billing cycle, a service tier/network and the clean-bandwidth allowance on the DDoS protection page, then click Continue to Checkout. On Complete Order, review the filtering region when offered, enter a Service Name, and review the Order Summary before submitting your order. Choose a region close to your backend and users; clean bandwidth measures delivered traffic, not attack traffic. If you already have a suitable active service, continue with that service.
Step 3: Encapsulation Setup (Required if listing server)
This step is only required if you are intending to use a GRE or IP-in-IP Tunnel. If you are intending to use a Reverse Proxy (RP) style connection (the easiest) then you can skip this step.
OpenVPN usually works best over a tunnel. If you choose to run your server behind a Reverse Proxy setup you will be unable to route outgoing traffic over the tunnel (if desired / wanted).
An encapsulated backend requires support on the Backend Server, currently Windows and Linux Operating Systems are fully supported, with partial support for FreeBSD. Most Enterprise or even SOHO Routers also support GRE or IP-in-IP tunneling, if supported you may be able to configure the router to terminate the encapsulated network.
Open Services, find your service, and choose Action > Tunnels. Click Add Tunnel, select GRE in Tunnel type, and enter the backend server's public IP in Backend address. Retain the displayed GRE key unless your backend requires a tunnel without one, then click Save. The integrated form below is an alternative way to configure the same tunnel.
The completed example uses 203.0.113.10 as a documentation-only backend address, GRE key 1785302134, and MTU 1472. Replace the backend address with your server’s public IP and use the same key and MTU when configuring that server.
After saving a port that uses this tunnel in Step 4, return to Tunnels and choose the tunnel's Action > Setup Tunnel. Select Linux / BSD and Download Tunnel Script, or Microsoft Windows and Download Application, as appropriate for your backend. The tunnel must be referenced by an Encapsulated port before it is usable. Install the downloaded script or application on your backend using the linked operating-system instructions.
See the GRE/IP-in-IP tunnel setup instructions.
Step 4: Add Ports
Add the ports required to run your service. OpenVPN by default uses port 1194 (TCP or UDP) as the main server port. The exact port you use and the most ideal depends on your desired setup. From us you may use any reasonable port. We do however advise against using ports that may have mitigation profiles applied to them such as UDP 53.
If unsure you can determine what port(s) the service bound to by using the ss or netstat commands as appropriate.
Open Services, find your service, and choose Action > Ports. Under Single Port, click Add port manually when Add your first port is shown; otherwise click Add Port. Enter the public port in Port start, choose the documented Protocol, and set Backend method to Reverse Proxy with your Backend address and Backend port, or to the available Encapsulated method with the tunnel created in Step 3. Click Save after each new entry and check the saved row. For a range, choose Port Range > Add Port Range, enter Port start and Port end, then select the protocol and backend before saving.
The completed example uses 203.0.113.10 as a documentation-only backend address. Replace it with your backend address, or select the GRE tunnel you created when using encapsulation.
Step 5: Test
Once all steps are completed and the progress bar for deployment of the configuration reaches 100% you should be able to connect to your service on your Filtered IP.
This Filtered IP is the address that you should use in any DNS names, or supply to any connecting users. All traffic which arrives at configured ports on a Filtered IP will be filtered for attack, and then forwarded to your configured backend server.
Note: Keep host and provider firewalls enabled. Allow the required service traffic from the current Backend Communication IP Addresses shown in the Dashboard. For tunnels, also allow the selected tunnel protocol between its endpoints.
Step 6: Outgoing connection support
If you desire outgoing connections to be routed out and over the protected service you will need to setup your protection using a GRE or IP-in-IP tunnel. Once setup you will need to bind the OpenVPN daemon to the network interface (Windows) or encapsulated 10.x.x.x IP (Linux).
For this particular application the Budget line services may be easier as they have only a single tunnel. For Anycast services you may choose to have either a single tunnel or multiple. When making an outgoing connection on an Anycast product you may notice a slight delay while the connection is initialized. This is us finding the correct PoP to handle your outgoing connection and creating the subsequent routes.
We do not recommend performing large amounts of ICMP or DNS over your protected IP as these may be filtered by the mitigation system.
