amazon-openvpn-ddns

• Provide an alternative to set up OpenVPN Server in EC2.
• Enable Dynamic Domain Name mapping to changing Elastic IP due to stopped instance.
• See example here.

Input Variables

Variable name	Description	Default
AWS_REGION	AWS Service Region to deploy	eu-west-2
prefix	Project Name
vpc_id	VPC ID
openvpn_server_ami	Any Ubuntu AMI (tested in eu-west-2 ubuntu 22.04 amd64)
subnet_id	Subnet ID that OpenVPN server will be deployed to
instance_type	OpenVPN Server Instance type	t2.small
admin_pwd	Admin Password for OpenVPN Server
email	Email to register ssl certificate for your subdomain.domain
subdomain	Subdomain, like prefix of api.google.com, it is api
domain	Domain, like google.com
public_key_openssh	Generate your ssh key and put public key here

How to Launch?

1. Run terraform to deploy.

   terraform init
   terraform apply -auto-approve

2. Change your hostname when you have access to subdomain.domain/admin.
   • Configuration -> Network Settings -> Hostname or IP Address -> Enter your subdomain.domain.
3. Check VPN Settings.
   • EC2 should have a private ip address, like 10.1.2.214.
   • VPC cidr is 10.1.0.0/16.
   • Change Network Address to 10.1.16.0.
   • Group Default IP Address Network (Optional) to 10.1.16.0/20.
   • Have clients use specific DNS Servers -- YES : Primary 10.1.0.2
   • YES using NAT.
   • VERY IMPORTANT -- Specify the private subnets to which all clients should be given access (one per line).
   • VERY IMPORTANT -- Specify the network address to which does not conflict with any CIDR. For example, API on 10.1.16.0/21, avoid using 10.1.16.0 because it will make the openvpn unreachable to API.

sequenceDiagram
  client->>route53: xxx.xxx.xxx vpn access
  route53->>client: public ip address
  box Aqua AWS
  participant openvpn access server(ec2)
  participant private subnet resources
  end
  client->>openvpn access server(ec2): ssh/vpn
  openvpn access server(ec2)->private subnet resources: 
  Note over openvpn access server(ec2),private subnet resources: Access
  loop Every day, Reboot
    openvpn access server(ec2)-->route53: Update IP
  end

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