Setting up Raspberry Pi as an OpenVPN client for the NETGEAR R7000 Nighthawk router

Since OpenVPN isn’t too chatty about failures in its default configuration, this took me a couple of tries to get right. Hopefully this post can save you some of the time I wasted .

In the following example, I’m assuming you already have a Raspberry Pi, running Raspbian and that you can access it over the local network. From the snippets below, change the example ip 192.168.3.14, to the ip of your local device.

Router

Start off by enabling the vpn service on the router, by going to ADVANCED > Advanced Setup > VPN Service, then check off Enable VPN Service and then click Apply.

When that is done and the router has rebooted, go back to the same page and download the VPN configuration zip file, nonwindows.zip, and copy it to the Pi:

rene $ scp nonwindows.zip pi@192.168.3.14:

Pi

Log in to the Pi and set up OpenVPN:

rene $ ssh pi@192.168.3.14
pi:~$ sudo apt-get update && sudo apt-get install openvpn

Once the installation is complete, add the configuration to openvpn:

pi:~$ unzip nonwindows.zip
pi:~$ sudo cp client2.conf ca.crt client.crt client.key /etc/openvpn/
pi:~$ sudo chown root:root /etc/openvpn/{client2.conf,ca.crt,client.crt,client.key}
pi:~$ sudo chmod 600 /etc/openvpn/{client2.conf,ca.crt,client.crt,client.key}
pi:~$ ls -la /etc/openvpn/
total 28
drwxr-xr-x  2 root root 4096 Jul 13 14:13 .
drwxr-xr-x 70 root root 4096 Jul 13 14:44 ..
-rw-------  1 root root 1253 Jul 13 13:57 ca.crt
-rw-------  1 root root 3576 Jul 13 13:57 client.crt
-rw-------  1 root root  891 Jul 13 13:57 client.key
-rw-------  1 root root  180 Jul 13 13:57 client2.conf
-rwxr-xr-x  1 root root 1301 Nov 19  2015 update-resolv-conf

Assuming you’re the only one accessing this Pi, setting the owner and file permissions isn’t strictly necessary, but nevertheless good practice. There’s no reason the these files should be readable by anyone but root.

Next you should edit /etc/default/openvpn and add a directive for the new configuration to start on boot:

AUTOSTART="client2"

Now reboot the Pi and verify that a new network device has been added for the remote network:

pi:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr b8:27:eb:1c:fa:81
          inet addr:10.0.0.4  Bcast:10.0.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST DYNAMIC  MTU:1500  Metric:1
          RX packets:4228 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1781 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:820993 (801.7 KiB)  TX bytes:246368 (240.5 KiB)
 
lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:13 errors:0 dropped:0 overruns:0 frame:0
          TX packets:13 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:1320 (1.2 KiB)  TX bytes:1320 (1.2 KiB)
 
tap0      Link encap:Ethernet  HWaddr da:dd:3a:80:50:7c
          inet addr:192.168.1.7  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST DYNAMIC  MTU:1500  Metric:1
          RX packets:621 errors:0 dropped:0 overruns:0 frame:0
          TX packets:177 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:70344 (68.6 KiB)  TX bytes:15922 (15.5 KiB)

Et voilà, that should be all there is to it!

Addendum

In case something didn’t quite go as planned, enabling some logging might be a good idea. Here’s a filtered list of options related to logging:

pi:~$ openvpn --help | grep log
--topology t    : Set --dev tun topology: 'net30', 'p2p', or 'subnet'.
                  as the program name to the system logger.
--syslog [name] : Output to syslog, but do not become a daemon.
--log file      : Output log to file which is created/truncated on open.
--log-append file : Append log to file, or create file if nonexistent.
--suppress-timestamps : Don't log timestamps to stdout/stderr.
--echo [parms ...] : Echo parameters to log output.
--management-log-cache n : Cache n lines of log file history for usage
--mute-replay-warnings : Silence the output of replay warnings to log file.
--pkcs11-cert-private [0|1] ... : Set if login should be performed before

To make use of one of these options, it used to be that the parameters could be passed in the OPTARGS directive of /etc/default/openvpn, but since OpenVPN has moved to using systemd, this is no longer supported. Relevant bug report.

Instead it is necessary to set them directly in each configuration. E.g. to enable append logging to a file add, edit /etc/openvpn/client2.conf and add the following line:

log-append /var/log/openvpn.log

According the the man page verbosity is set from 0-11, and by default the vpn configuration from the R7000 has verbosity set to 5. This means the log file can quickly become rather large if left in append mode unattended, so make sure you have enough room on the SD card or remove the option again, when you are done debugging. Alternatively use –management-log-cache or truncate on each run by just using –log.

N.B. In my experience the client can be a bit flaky at times and I’ve often seen the first many connection attempts end in the following errors:

TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
TLS Error: TLS handshake failed

And then after a number of tries, suddenly come through. Don’t ask me why.

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