How To Debug and Fix PPTP/VPN Client Connection

I am asking a question, which has two sub-questions. Those are how can I get VPN to work on Ubuntu 12.04, either by getting the built-in pptp VPN to work or through manual configuration. Microsoft clients have no trouble creating VPN connections into the same system.

Here are the details:

I am running Ubuntu 12.04

Linux mrshighpants 3.2.0-40-generic-pae 
#64-Ubuntu SMP Mon Mar 25 21:44:41 
UTC 2013 i686 i686 i386 GNU/Linux

For this version of Ubuntu and quite a few releases going back, I can configure VPN using Network Manager, but cannot get it to start. On 12.04, I get the service did not start for an error message.

1) What is the best way to debug this?

2) I would like to enhance this question by providing the necessary logs, but what data should I place in this question, other than tail syslog (shown below)?

3) Is there a way to get VPN configured manually?

Here is tail syslog

tail syslog

May 11 16:27:51 mrshighpants NetworkManager[868]: <info> Starting VPN service 'pptp'...
May 11 16:27:51 mrshighpants NetworkManager[868]: <info> VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 3552
May 11 16:27:51 mrshighpants NetworkManager[868]: <info> VPN service 'pptp' appeared; activating connections
May 11 16:27:51 mrshighpants NetworkManager[868]: <info> VPN plugin state changed: init (1)
May 11 16:27:51 mrshighpants NetworkManager[868]: <info> VPN plugin state changed: starting (3)
May 11 16:27:51 mrshighpants NetworkManager[868]: <info> VPN connection 'townofsomethington' (Connect) reply received.
May 11 16:27:51 mrshighpants NetworkManager[868]: <warn> VPN connection 'townofsomethington' failed to connect: 'couldn't convert PPTP VPN gateway IP address '123.4.5.281' (0)'.
May 11 16:27:51 mrshighpants NetworkManager[868]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active.
May 11 16:27:51 mrshighpants NetworkManager[868]: <info> Policy set 'MtLaughmore' (wlan0) as default for IPv4 routing and DNS.
May 11 16:27:56 mrshighpants NetworkManager[868]: <info> VPN service 'pptp' disappeared

After Testing:

There were two problems, and now a successful connection. The IP address was interposed .281, instead of 218, and the password was wrong.

Solution 1:

Check your settings with it.

VPN connection in Ubuntu

Go to network manager > VPN Connection > Configure VPN > Add VPN

1. Name VPN Connection ( Any Name )

2. Gateway : You ip address of pptp server Or FDDN ( Fully Qualified Domain Name )

3. User Name

4. Password

5. Click on Advanced

Click on " Use point to point encryption " Click OK & Save

Now open terminal

 tail -f /var/log/syslog

And just connect to VPN & check your logs.

Solution 2:

There is a typographical failure:

[...]'couldn't convert PPTP VPN gateway IP address '209.6.3.281' (0)'[...]

This IP can't exist cause the last number 281 is greater than 255.

Solution 3:

The instructions provided at Debugging NetworkManager pptp look like a good option for debugging VPN connections configured using NetworkManager:

1. in a root terminal, run:

   killall -TERM nm-pptp-service

   /usr/libexec/nm-pptp-service --debug # This is one potential path, OR

   /usr/lib/NetworkManager/nm-pptp-service --debug # Ubuntu 14.04 LTS

2. start your VPN connection

3. reproduce the problem