Perimeter 81 offers a designated native Linux app, available here, so keep reading only if you manually configured your connection using OpenVPN Manager.
The most common issue that might prevent you from accessing the web after performing a manual configuration of Perimeter 81 in your Linux machine is related to LZO settings.
In order to make sure LZO settings are set correctly follow these instructions:
If you are running Ubuntu 18.0.4 (or a later version)
1. Go to the Linux OS Settings section and choose the OpenVPN Advanced Options.
2. Check the Use LZO data compression checkbox and select no.
If you are running an older version
Go to the Linux OS Settings section and choose the OpenVPN Advanced Options. Make sure that LZO compression is disabled, by unchecking the checkbox: