What technique can be used to troubleshoot connectivity issues on a video conferencing device while maintaining firewall security?

Using VPN access through the firewall is an effective technique to troubleshoot connectivity issues on a video conferencing device while ensuring security. By configuring the firewall to provide VPN access, you create a secure tunnel through which authorized users can access the video conferencing device without exposing it directly to potential threats from the internet. This method maintains the integrity of firewall security policies while allowing remote troubleshooting and management.

With VPN access, network traffic is encrypted, ensuring that only authenticated users can connect to the network and reach the conferencing device, thus protecting sensitive data. It enables IT professionals to troubleshoot connectivity issues without compromising security by exposing the device directly to untrusted networks.

In contrast, the other options could potentially undermine security or facilitate unauthorized access. For example, establishing a second network connection directly to the device may lead to an unwanted increase in attack surfaces. Allowing all use of UDP below or denying all use of UDP above certain ports could disrupt normal operations or fail to address the specific issues related to troubleshooting video conferencing, which often requires specific ports and protocols to function correctly.