Troubleshooting routing issues
Most of the questions asked on the OpenVPN e-mail lists and user forums are actually routing questions. Setting up a VPN connection is one thing, but integrating it into your existing network is quite another. To a novice, the difficult part is to see where OpenVPN stops and where routing begins. This section is intended as a step-by-step guide to troubleshoot routing issues in a fairly basic OpenVPN setup.
Consider the following network plan:
The network at the main office location needs to be made accessible to a secondary office and to people working from home
The servers in the secondary office needs to be made accessible to the IT department of the main office
The people working from home only need to access the computer resources at the main office
For this, an OpenVPN server is set up at the main office, with the employees connecting as regular VPN clients, and with the secondary office connecting as a special client, disclosing its own network.