Linux Tactic

Secure Your Online Presence: Setting Up Your Own OpenVPN Server for Ultimate Privacy

Introduction to VPN and the Importance of

Setting Up Your Own VPN Server

In today’s digital age, the internet is an essential part of our lives. It connects us to the world, allowing us to access information, communicate with others, and conduct business online.

But with these conveniences come risks to our online security and privacy. This is where VPN comes in.

A virtual private network (VPN) is a technology that creates a secure and private connection between your device and the internet. It encrypts your traffic, making it impossible for anyone to intercept or eavesdrop on your online activity.

In this article, we will explore the benefits of using a VPN and show you how to set up your own VPN server.

Benefits of Using a VPN

Internet Safety: One of the primary benefits of using a VPN is enhanced internet safety. VPNs encrypt your online traffic, protecting it from prying eyes.

For example, if you’re using public Wi-Fi at a coffee shop or airport, your information can easily be intercepted by hackers. With a VPN, your data is encrypted, making it much more difficult for someone to steal.

Secure Wi-Fi: This leads to the next benefit, secure Wi-Fi. By using a VPN, you can ensure that your information is safe when connected to a Wi-Fi network. This is important, particularly when traveling or in areas where Wi-Fi networks may not be secure.

Bypass Geo-Restricted Content: One of the most popular reasons people use VPNs is to bypass geo-restricted content. Some content, such as movies and TV shows, may only be available in certain regions.

By using a VPN, you can change your virtual location, allowing you to bypass these restrictions and access the content you want. Secure Company Network: VPNs are also commonly used by businesses to secure their networks.

They can protect sensitive data and provide secure remote access for employees who need to work from outside the office. VPN Providers: While there are many VPN providers out there, it’s important to choose a reputable one.

Some VPN providers may keep logs of your online activity, compromising your privacy. Be sure to do your research and choose a provider that doesn’t log your activity.

Setting Up Your Own VPN Server

While there are many VPN providers, setting up your own VPN server provides a significant level of control, customization, and security. OpenVPN is an open-source VPN solution that is widely used and has many features.

Here are some steps to get you started:

Install and Configure OpenVPN: The first step is to install and configure OpenVPN. The installation process will vary depending on the server you’re using.

However, for Debian 9, you can use the “apt-get” command to install OpenVPN. Generate Client Certificates: Once OpenVPN is installed, you’ll need to generate client certificates.

This is done using a certificate authority (CA), which is a separate machine that issues and signs digital certificates. The CA machine needs to be configured with EasyRSA, a certificate management tool.

Create Configuration Files: The final step is to create configuration files for your clients. These files will tell the clients how to connect to the VPN server and what encryption settings to use.

Conclusion

In conclusion, VPNs are an essential tool for anyone who values their online privacy and security. By using a VPN, you can protect your online activity, bypass geo-restricted content, and secure your company’s network.

While many VPN providers are available, setting up your own VPN server provides a higher level of customization and control. With OpenVPN, the process is straightforward and provides a reliable solution for securing your online activity.

Building Certificate Authority (CA) with EasyRSAto PKI

Public Key Infrastructure (PKI) is a system that uses encryption and digital certificates to secure communications over the internet. It involves the use of Certificate Authority (CA) certificates, which are digital certificates that verify the identity of the client and the server.

These certificates are used to establish secure connections between the two parties, allowing for the safe transmission of data. When setting up a VPN server, it’s essential to establish a PKI system using a CA certificate.

This certificate is used to sign digital certificates for both the server and the clients.

Building CA with EasyRSA

EasyRSA is a command-line utility that allows for the easy generation and management of a PKI system. Building a CA with EasyRSA involves several steps:

1.

Install OpenSSL – EasyRSA requires OpenSSL to be installed on the machine that will act as the CA. This can be done using the package manager of your operating system.

2. Set up the CA machine – The CA machine should be a separate machine from the VPN server.

This ensures that the CA’s private key is not compromised if the VPN server is hacked. Once the machine is set up, download and extract EasyRSA.

3. Generate certificate requests – The certificate requests are generated for both the server and each client.

These are essentially digital documents that contain information about the applicant, such as name, location, and organization. 4.

Sign certificates – The certificate requests are then signed by the CA. This involves validating the applicant’s identity and creating a digital certificate that can be used to establish secure connections with the VPN server.

Creating Diffie-Hellman and HMAC Keys

Generating Diffie-Hellman Key

Diffie-Hellman (DH) is a key exchange algorithm that allows two parties to establish a shared secret key over an insecure network. This is essential for establishing a secure connection between two parties.

To generate a DH key in OpenVPN, the following steps can be followed:

1. Open the terminal and navigate to the directory where the OpenVPN configuration files are located.

2. Type the following command to generate a 2048-bit long DH parameter: “openssl dhparam -out dh2048.pem 2048”

3.

This command will create a file called “dh2048.pem” that contains the DH parameters. These parameters should be copied to the OpenVPN configuration file.

4. To configure OpenVPN to use the DH file, add the following line to the configuration file: “dh dh2048.pem”

Generating HMAC Signature

To add an additional layer of security to OpenVPN, an HMAC signature can be added. This signature verifies the integrity of the packets sent between the client and server, preventing any unauthorized modification.

To generate an HMAC signature, the following steps can be followed:

1. Open the terminal and navigate to the directory where the OpenVPN configuration files are located.

2. Type the following command to generate the HMAC signature: “openvpn –genkey –secret ta.key”

3.

This command will create a file called “ta.key” that contains the HMAC signature. 4.

To configure OpenVPN to use the HMAC signature, add the following line to the configuration file: “tls-auth ta.key 0”

Conclusion

Building a Certificate Authority with EasyRSA is an essential step in securing your OpenVPN server. A proper PKI system helps ensure that communications between the server and clients are secure and private.

Additionally, generating Diffie-Hellman and HMAC keys provides an extra layer of security that can help protect against unauthorized access. By following the steps outlined in this article, you can establish a secure and reliable VPN server for your organization.

Creating Server Certificate and Private Key

Generating Private Key and Certificate Request

To establish a secure connection between the client and server, a server certificate is needed. This certificate contains the server’s public key and other identifying information.

To create the certificate and private key, the following steps can be followed:

1. Open the terminal and navigate to the directory where the EasyRSA files are located.

2. Copy the “vars.example” file to a new file called “vars”: “cp vars.example vars”

3.

Edit the “vars” file to include the correct variables for your organization. 4.

Execute the following command to initialize EasyRSA: “source ./vars”

5. Execute the following command to build the server’s private key and certificate request: “./easyrsa gen-req server nopass”

6.

This command will generate two files: “server.key” and “server.req”. The private key (“server.key”) should be kept secure, and the certificate request (“server.req”) will be used to generate the server certificate.

Signing the Certificate Request

To sign the server certificate request with the Certificate Authority (CA), the following steps can be taken:

1. Navigate to the EasyRSA directory in the terminal.

2. Execute the following command to import the CA’s public key: “./easyrsa import-req /path/to/server.req server”

3.

Execute the following command to sign the server certificate with the CA’s private key: “./easyrsa sign-req server server”

4. This command will generate a server certificate (“issued server.crt”) that can be used to authenticate the server.

Configuring the OpenVPN Service

Starting OpenVPN Service

To start the OpenVPN service, the following steps can be taken:

1. Copy the OpenVPN configuration file to the /etc/openvpn/ directory: “cp /path/to/ovpn/file /etc/openvpn/server.conf”

2.

Create a systemd unit file for OpenVPN: “nano /etc/systemd/system/openvpn.service”

3. In the editor, add the following lines:

“`

[Unit]

Description=OpenVPN service

After=network.target

[Service]

Type=oneshot

ExecStart=/usr/sbin/openvpn –config /etc/openvpn/server.conf

ExecReload=/usr/sbin/openvpn –config /etc/openvpn/server.conf –signal SIGUSR1

RemainAfterExit=yes

[Install]

WantedBy=multi-user.target

“`

4.

Save the file and close the editor. 5.

Enable the service to start at boot: “systemctl enable openvpn.service”

6. Start the service: “systemctl start openvpn.service”

IP Forwarding and Firewall Configuration

To enable IP forwarding and configure the firewall, the following steps can be taken:

1. Enable IP forwarding by editing the sysctl configuration file: “nano /etc/sysctl.conf”

2.

Uncomment the following line: “net.ipv4.ip_forward=1”

3. Save the file and close the editor.

4. Apply the changes: “sysctl -p /etc/sysctl.conf”

5.

Configure the firewall to allow traffic to pass through: “ufw allow OpenSSH”

6. Enable masquerading: “echo 1 > /proc/sys/net/ipv4/ip_forward”; “sudo iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE”

7.

Configure port forwarding to forward traffic from the internet to the VPN server: “sudo iptables -A INPUT -p tcp –dport 1194 -j ACCEPT”; “sudo iptables -A FORWARD -s 10.8.0.0/24 -j ACCEPT”; “sudo iptables -A FORWARD -m state –state RELATED,ESTABLISHED -j ACCEPT”; “sudo iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE”; “sudo iptables -A INPUT -p udp –dport 1194 -j ACCEPT”

Conclusion

By creating a server certificate and configuring the OpenVPN service, you can establish a secure and reliable VPN server. Enabling IP forwarding and configuring the firewall are both essential steps to ensure that the server is accessible and secure for remote clients.

By following the steps outlined in this article, you can set up a VPN server that provides a secure and private connection for your organization.

Creating the Client Configuration Infrastructure

Setting Up Directories and Copying Base Files

To create the client configuration infrastructure, the following steps can be taken:

1. Create a directory structure to store the client files: “mkdir -p ~/client-configs/files”

2.

Copy the base files into the client configuration directory: “cp /usr/share/doc/openvpn/examples/sample-config-files/client.conf ~/client-configs/base.conf” and “cp /etc/openvpn/easy-rsa/2.0/keys/ca.crt ~/client-configs/”

3. Open the base configuration file: “nano ~/client-configs/base.conf”

4.

Edit the file to include the correct server address and port, as well as the ca, cert, and key file locations:

“`

remote YOUR_SERVER_IP_ADDRESS PORT

ca ca.crt

cert CLIENT.crt

key CLIENT.key

“`

5. Save the file and close the editor.

Generating Client Certificate Private Key and Configuration

To generate the client certificate private key and configuration, the following steps can be taken:

1. Navigate to the EasyRSA directory in the terminal: “cd /etc/openvpn/easy-rsa”

2.

Set the necessary environment variables: “source ./vars”

3. Execute the following command to generate a client private key and certificate request: “./easyrsa gen-req CLIENT_NAME nopass”

4.

This command will generate two files: “CLIENT_NAME.key” and “CLIENT_NAME.req”. The private key (“CLIENT_NAME.key”) should be kept secure, and the certificate request (“CLIENT_NAME.req”) will be used to generate the client certificate.

5. To sign the client certificate request with the CA, execute the following command: “./easyrsa sign-req client CLIENT_NAME”

6.

This command will generate a client certificate (“issued CLIENT_NAME.crt”). Copy this file to the client configuration directory: “cp /etc/openvpn/easy-rsa/pki/issued/CLIENT_NAME.crt ~/client-configs/files/”

7.

Create a script to automate the client configuration process: “nano ~/client-configs/make_config.sh”

8. In the editor, add the following lines:

“`

#!/bin/bash

# First argument: Client identifier

KEY_DIR=~/client-configs/keys

OUTPUT_DIR=~/client-configs/files

BASE_CONFIG=~/client-configs/base.conf

cat ${BASE_CONFIG}

<(echo -e '‘)

${KEY_DIR}/ca.crt

<(echo -e 'n‘)

${KEY_DIR}/${1}.crt

<(echo -e 'n‘)

${KEY_DIR}/${1}.key

<(echo -e 'n‘)

${KEY_DIR}/ta.key

<(echo -e '‘)

> ${OUTPUT_DIR}/${1}.ovpn

“`

9.

Save the file and close the editor. 10.

Make the script executable: “chmod +x ~/client-configs/make_config.sh”

Connecting Clients

Connecting Clients on Linux

To connect clients on Linux, the following steps can be taken:

1. Open the terminal and navigate to the client configuration directory: “cd ~/client-configs/files”

2.

Type the following command to connect to the OpenVPN server: “sudo openvpn –config CLIENT_NAME.ovpn”

3. Enter your user password if prompted.

4. The client should now be connected to the VPN server.

Connecting Clients on macOS

To connect clients on macOS, the following steps can be taken:

1. Install the Tunnelblick application if it’s not already installed.

2. Copy the client configuration file (“CLIENT_NAME.ovpn”) to the OpenVPN configuration folder: “~/Library/Application Support/Tunnelblick/Configurations”

3.

Open the Tunnelblick application and click “Connect” next to the client configuration file. 4.

Enter your macOS user password if prompted. 5.

The client should now be connected to the VPN server.

Connecting Clients on Windows

To connect clients on Windows, the following steps can be taken:

1. Download and install the OpenVPN application if it’s not already installed.

2. Copy the client configuration file (“CLIENT_NAME.ovpn”) to the OpenVPN config folder: “C:Program FilesOpenVPNconfig”

3.

Right-click on the OpenVPN icon in the system tray and select the client configuration file to connect. 4.

Enter your Windows user password if prompted. 5.

The client should now be connected to the VPN server. Connecting Clients on Android & iOS

To connect clients on Android and iOS, the following steps can be taken:

1.

Download and install the OpenVPN Connect application from the respective app store. 2.

Transfer the client configuration file (“CLIENT_NAME.ovpn”) to your device. 3.

Open the OpenVPN Connect application and import the client configuration file. 4.

Enter any additional login or authentication details if prompted. 5.

The client should now be connected to the VPN server.

Conclusion

By creating the client configuration infrastructure and connecting clients to the VPN server, you can establish secure and reliable connections from various devices. Setting up the necessary directories, generating the client certificate private key and configuration, and configuring the client software for different operating systems will ensure smooth and secure connectivity.

By following the steps outlined in this article, you can successfully connect clients to your OpenVPN server and enjoy the benefits of a secure and private network.

Revoking Client Certificates

Revoking Client Certificates

In certain situations, it may become necessary to revoke a client’s certificate. This could be due to concerns of compromised security, a client’s departure from the organization, or any other reason that would require invalidating a previously signed certificate.

OpenVPN provides the functionality to revoke client certificates, ensuring that these certificates can no longer be used to establish a connection to the server.

Steps to Revoke Client Certificates

To revoke a client certificate, the following steps can be taken:

1. Access the OpenVPN server where the certificate authority (CA) files are stored.

2. Navigate to the EasyRSA directory within the OpenVPN configuration directory: “/etc/openvpn/easy-rsa”.

3. Execute the following command to revoke the certificate for a specific client: “./easyrsa revoke CLIENT_NAME”.

4. This command will generate a certificate revocation list (CRL), which contains information about the revoked certificate.

5. Update the CRL: “./easyrsa gen-crl”.

6. Copy the generated CRL file (“crl.pem”) to the OpenVPN directory: “cp /etc/openvpn/easy-rsa/pki/crl.pem /etc/openvpn/crl.pem”.

7. Finally, restart the OpenVPN service for the changes to take effect: “systemctl restart openvpn”.

By following these steps, the OpenVPN server will deny any connection attempts made using the revoked certificate, ensuring the security and integrity of the VPN environment.

Conclusion

In this article, we have covered essential aspects of setting up an OpenVPN server and establishing a secure VPN connection. We discussed the benefits of using a VPN and the importance of setting up your own VPN server, highlighting the advantages of internet safety, secure Wi-Fi, bypassing geo-restricted content, and securing company networks.

We explored the overview of OpenVPN and its prerequisites, emphasizing the fully featured VPN solution it provides and the requirements for installation. We then delved into building the certificate authority (CA) with EasyRSA, which is crucial for creating a secure PKI system for your OpenVPN server.

Furthermore, we covered the steps for creating Diffie-Hellman and HMAC keys to enhance security. Configuring the OpenVPN service, enabling IP forwarding and firewall configuration were discussed to ensure smooth communication between clients and the server.

We also addressed the creation of the client configuration infrastructure, including setting up directories, generating client certificate private keys and configurations, and connecting clients on various operating systems. Revoking client certificates was highlighted as an important capability to maintain the security of the OpenVPN server.

Alongside that, we provided steps to revoke client certificates and update the certificate revocation list (CRL) to prevent any unauthorized access. In summary, by following the steps presented in this article, you can successfully set up and configure an OpenVPN server, create client configurations, and establish secure connections between clients and the server.

Should any issues or problems arise during the setup or configuration process, it is recommended to seek assistance from the OpenVPN community or professional support to ensure a smooth and secure VPN deployment. In conclusion, setting up a VPN server and establishing secure connections through OpenVPN is crucial for safeguarding your online presence.

By understanding the benefits of using a VPN, such as enhanced internet safety and the ability to bypass geo-restricted content, you can take control of your online privacy. Building a certificate authority with EasyRSA, configuring the OpenVPN service, and creating the client configuration infrastructure are essential steps in establishing a secure VPN environment.

Moreover, the ability to revoke client certificates ensures ongoing security. Remember, with the right knowledge and steps, you can create a reliable and protected VPN server, providing you and your organization with peace of mind in an increasingly interconnected world.

Secure your data, protect your privacy, and surf the internet with confidence.

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