How to setup vpn in ubuntu 12.04?

Question

linux

Configuration via GUI. I can’t leave only CHAP in the settings, it’s possible only with MS-CHAPv2 or with other options (the checkboxes are dependent on each other). In which files are the connection settings stored?
Connection event log with active CHAP and MS-CHAPv2:

spoiler

Dec 22 21:19:13 ubuntu NetworkManager[919]: Starting VPN service 'pptp'...
Dec 22 21:19:13 ubuntu NetworkManager[919]: VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 3844
Dec 22 21:19:13 ubuntu NetworkManager[919]: VPN service 'pptp' appeared; activating connections
Dec 22 21:19:13 ubuntu NetworkManager[919]: VPN plugin state changed: init (1)
Dec 22 21:19:13 ubuntu NetworkManager[919]: VPN plugin state changed: starting (3)
Dec 22 21:19:13 ubuntu NetworkManager[919]: VPN connection 'myProvider' (Connect) reply received.
Dec 22 21:19:13 ubuntu pppd[3848]: Plugin /usr/lib/pppd/2.4.5/nm-pptp-pppd-plugin.so loaded.
Dec 22 21:19:13 ubuntu pppd[3848]: pppd 2.4.5 started by root, uid 0
Dec 22 21:19:13 ubuntu pppd[3848]: Using interface ppp0
Dec 22 21:19:13 ubuntu pppd[3848]: Connect: ppp0 <--> /dev/pts/0
Dec 22 21:19:13 ubuntu pptp[3851]: nm-pptp-service-3844 log[main:pptp.c:314]: The synchronous pptp option is NOT activated
Dec 22 21:19:13 ubuntu NetworkManager[919]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Dec 22 21:19:13 ubuntu NetworkManager[919]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
Dec 22 21:19:13 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request'
Dec 22 21:19:13 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply
Dec 22 21:19:13 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established.
Dec 22 21:19:14 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request'
Dec 22 21:19:14 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply.
Dec 22 21:19:14 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer's call ID 38402).
Dec 22 21:19:20 ubuntu pppd[3848]: CHAP authentication succeeded: Welcome
Dec 22 21:19:20 ubuntu pppd[3848]: CHAP authentication succeeded
Dec 22 21:19:20 ubuntu pppd[3848]: LCP terminated by peer
Dec 22 21:19:20 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_disp:pptp_ctrl.c:929]: Call disconnect notification received (call id 38402)
Dec 22 21:19:23 ubuntu pppd[3848]: Connection terminated.
Dec 22 21:19:23 ubuntu avahi-daemon[851]: Withdrawing workstation service for ppp0.
Dec 22 21:19:23 ubuntu NetworkManager[919]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Dec 22 21:19:23 ubuntu NetworkManager[919]: VPN plugin failed: 1
Dec 22 21:19:23 ubuntu pptp[3851]: nm-pptp-service-3844 warn[decaps_hdlc:pptp_gre.c:204]: short read (-1): Input/output error
Dec 22 21:19:23 ubuntu pptp[3851]: nm-pptp-service-3844 warn[decaps_hdlc:pptp_gre.c:216]: pppd may have shutdown, see pppd log
Dec 22 21:19:23 ubuntu pppd[3848]: Modem hangup
Dec 22 21:19:23 ubuntu pptp[3859]: nm-pptp-service-3844 log[callmgr_main:pptp_callmgr.c:234]: Closing connection (unhandled)
Dec 22 21:19:23 ubuntu pppd[3848]: Exit.
Dec 22 21:19:23 ubuntu NetworkManager[919]: VPN plugin failed: 1
Dec 22 21:19:23 ubuntu pptp[3859]: nm-pptp-service-3844 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request'
Dec 22 21:19:23 ubuntu pptp[3859]: nm-pptp-service-3844 log[call_callback:pptp_callmgr.c:79]: Closing connection (call state)
Dec 22 21:19:23 ubuntu NetworkManager[919]: VPN plugin failed: 1
Dec 22 21:19:23 ubuntu NetworkManager[919]: VPN plugin state changed: stopped (6)
Dec 22 21:19:23 ubuntu NetworkManager[919]: VPN plugin state change reason: 0
Dec 22 21:19:23 ubuntu NetworkManager[919]: error disconnecting VPN: Could not process the request because no VPN connection was active.
Dec 22 21:19:23 ubuntu NetworkManager[919]: Policy set 'local' (eth0) as default for IPv4 routing and DNS.
Dec 22 21:19:29 ubuntu NetworkManager[919]: VPN service 'pptp' disappeared
Dec 22 21:19:32 ubuntu kernel: [ 1763.397867] type=1400 audit(1387721972.553:31): apparmor="DENIED" operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=836 comm="cupsd" pid=836 comm="cupsd" capability=36 capname="block_suspend"

Answer 1

Settings are stored in /etc/NetworkManager/system-connections/ pptp will choose the working option itself, but apparently you have a different problem. The log shows that the server accepted in with CHAP and then disconnected for no reason.