Summary
In this chapter we have learned how to check our OpenVPN and networking setup step-by-step using standard Linux tools and evaluating their output. With tools like ifconfig, ping, traceroute, and mtr, we could analyze the flow of datagrams between the VPN servers and the connected networks. Programs like tcpdump, IPTraf, ntop, and Munin will give us detailed information about the current traffic or statistical breakdowns of it. The first place to look for troubleshooting should always be the log file of OpenVPN itself—especially at a higher level of verbosity.
