Troubleshooting OpenVPN Connection Drops on OpenBSD 7.6

Introduction

OpenVPN is a popular open-source Virtual Private Network (VPN) solution that provides secure and encrypted communication over the internet. OpenBSD is an operating system known for its robust security features. However, users of OpenBSD 7.6 with OpenVPN 2.6.12 may encounter connection drops. In this article, we will discuss the potential causes and solutions for OpenVPN connection drops on OpenBSD 7.6.

Prerequisites

To follow this guide, you should have:

• OpenBSD 7.6 installed on your system
• OpenVPN 2.6.12 installed using pkg_add

Potential Causes

OpenVPN connection drops on OpenBSD 7.6 can be caused by various reasons:

Firewall Rules

OpenBSD's default firewall rules may block OpenVPN traffic. You can check the firewall rules using the following command:

If you find that OpenVPN traffic is being blocked, you can add the following rules to the firewall:

And add the following lines to the /etc/pf.conf file:

Network Interface Configuration

Misconfigured network interfaces can also cause OpenVPN connection drops. Ensure that the OpenVPN interface is configured correctly in the /etc/hostname.tun0 file:

The IP address in the above example should be in the same subnet as your OpenVPN server.

TLS Handshake

OpenVPN uses the TLS handshake to establish a secure connection. If the TLS handshake fails, the connection will drop. This can be caused by outdated certificates or incorrect certificate configurations. To check the TLS handshake, you can use the following command:

Look for lines that indicate TLS handshake errors.

Solutions

To resolve OpenVPN connection drops on OpenBSD 7.6, you can try the following solutions:

Update Certificates

Ensure that your certificates are up-to-date. You can generate new certificates using the OpenVPN EasyRSA tool or obtain them from your OpenVPN service provider.

Configure Firewall

Configure your firewall to allow OpenVPN traffic as described in the "Firewall Rules" section above.

Configure Network Interfaces

Configure your network interfaces as described in the "Network Interface Configuration" section above.

Summary

OpenVPN connection drops on OpenBSD 7.6 can be caused by various reasons such as firewall rules, misconfigured network interfaces, and TLS handshake issues. To resolve these issues, you can update your certificates, configure your firewall, and ensure that your network interfaces are correctly configured. If you continue to experience connection drops, you may want to consult OpenBSD and OpenVPN documentation or seek assistance from the OpenBSD and OpenVPN communities.