pptp vpn does not work,connection failed

[zhiwei]

I can use this vpn a few days ago, I'm sure there is nothing wrong with the vpn server, and I didn't change my vpn client settings, after recently update, I can't use pptp vpn connection.

Ubuntu: 11.10 develop branch
Kernel: 3.0.0-12-generic
pptpd: v1.3.4
NetworkManger: 0.9.1.90

When I use this command to see NetworkManger version,it displays these words:
$ NetworkManager --version
Failed to read classid file: Object not found
0.9.1.90

The following message are in ubuntu syslog:

Oct 3 08:13:47 ubuntu dbus[892]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Oct 3 08:13:56 ubuntu kernel: [ 1347.778328] wlan0: no IPv6 routers present
Oct 3 08:13:57 ubuntu wpa_supplicant[1091]: WPA: Group rekeying completed with 40:16:9f:24:0e:5a [GTK=CCMP]
Oct 3 08:13:57 ubuntu nm-dispatcher.action: Script '/etc/NetworkManager/dispatcher.d/01ifupdown' exited with error status 1.
Oct 3 08:14:06 ubuntu NetworkManager[1044]: <info> (wlan0): IP6 addrconf timed out or failed.
Oct 3 08:14:06 ubuntu NetworkManager[1044]: <info> Activation (wlan0) Stage 4 of 5 (IP6 Configure Timeout) scheduled...
Oct 3 08:14:06 ubuntu NetworkManager[1044]: <info> Activation (wlan0) Stage 4 of 5 (IP6 Configure Timeout) started...
Oct 3 08:14:06 ubuntu NetworkManager[1044]: <info> Activation (wlan0) Stage 5 of 5 (IP Configure Commit) started...
Oct 3 08:14:06 ubuntu NetworkManager[1044]: <info> Activation (wlan0) Stage 5 of 5 (IP Configure Commit) complete.
Oct 3 08:14:06 ubuntu NetworkManager[1044]: <info> Activation (wlan0) Stage 4 of 5 (IP6 Configure Timeout) complete.
Oct 3 08:14:26 ubuntu ntpdate[2677]: adjust time server 91.189.94.4 offset 0.039240 sec
Oct 3 08:14:35 ubuntu NetworkManager[1044]: <info> Starting VPN service 'pptp'...
Oct 3 08:14:35 ubuntu NetworkManager[1044]: <info> VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 2690
Oct 3 08:14:35 ubuntu NetworkManager[1044]: <info> VPN service 'pptp' appeared; activating connections
Oct 3 08:14:35 ubuntu NetworkManager[1044]: <info> VPN plugin state changed: 1
Oct 3 08:14:43 ubuntu NetworkManager[1044]: <info> VPN plugin state changed: 3
Oct 3 08:14:43 ubuntu NetworkManager[1044]: <info> VPN connection 'windows vpn' (Connect) reply received.
Oct 3 08:14:43 ubuntu pppd[2696]: Plugin /usr/lib/pppd/2.4.5/nm-pptp-pppd-plugin.so loaded.
Oct 3 08:14:43 ubuntu pppd[2696]: pppd 2.4.5 started by root, uid 0
Oct 3 08:14:43 ubuntu pptp[2701]: nm-pptp-service-2690 log[main:pptp.c:314]: The synchronous pptp option is NOT activated
Oct 3 08:14:43 ubuntu pptp[2707]: nm-pptp-service-2690 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request'
Oct 3 08:14:43 ubuntu pppd[2696]: Using interface ppp0
Oct 3 08:14:43 ubuntu pppd[2696]: Connect: ppp0 <--> /dev/pts/0
Oct 3 08:14:43 ubuntu NetworkManager[1044]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Oct 3 08:14:43 ubuntu NetworkManager[1044]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
Oct 3 08:14:43 ubuntu pptp[2707]: nm-pptp-service-2690 log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply
Oct 3 08:14:43 ubuntu pptp[2707]: nm-pptp-service-2690 log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established.
Oct 3 08:14:44 ubuntu pptp[2707]: nm-pptp-service-2690 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request'
Oct 3 08:14:44 ubuntu pptp[2707]: nm-pptp-service-2690 log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply.
Oct 3 08:14:44 ubuntu pptp[2707]: nm-pptp-service-2690 log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer's call ID 1762).
Oct 3 08:15:14 ubuntu pppd[2696]: LCP: timeout sending Config-Requests
Oct 3 08:15:14 ubuntu pppd[2696]: Connection terminated.
Oct 3 08:15:14 ubuntu avahi-daemon[968]: Withdrawing workstation service for ppp0.
Oct 3 08:15:14 ubuntu NetworkManager[1044]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Oct 3 08:15:14 ubuntu NetworkManager[1044]: <warn> VPN plugin failed: 1
Oct 3 08:15:14 ubuntu pptp[2701]: nm-pptp-service-2690 warn[decaps_hdlc:pptp_gre.c:204]: short read (-1): Input/output error
Oct 3 08:15:14 ubuntu pppd[2696]: Modem hangup
Oct 3 08:15:14 ubuntu pptp[2701]: nm-pptp-service-2690 warn[decaps_hdlc:pptp_gre.c:216]: pppd may have shutdown, see pppd log
Oct 3 08:15:14 ubuntu pptp[2707]: nm-pptp-service-2690 log[callmgr_main:pptp_callmgr.c:234]: Closing connection (unhandled)
Oct 3 08:15:14 ubuntu pptp[2707]: nm-pptp-service-2690 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request'
Oct 3 08:15:14 ubuntu pptp[2707]: nm-pptp-service-2690 log[call_callback:pptp_callmgr.c:79]: Closing connection (call state)
Oct 3 08:15:14 ubuntu pppd[2696]: Exit.
Oct 3 08:15:14 ubuntu NetworkManager[1044]: <warn> VPN plugin failed: 1
Oct 3 08:15:14 ubuntu NetworkManager[1044]: <info> VPN plugin state changed: 6
Oct 3 08:15:14 ubuntu NetworkManager[1044]: <info> VPN plugin state change reason: 0
Oct 3 08:15:14 ubuntu NetworkManager[1044]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active.
Oct 3 08:15:14 ubuntu NetworkManager[1044]: <info> Policy set 'TP-LINK' (wlan0) as default for IPv4 routing and DNS.
Oct 3 08:15:19 ubuntu NetworkManager[1044]: <info> VPN service 'pptp' disappeared

[zhiwei (chenzhiwei)]

The problem is due to ISP of my area.

[Jussi Lind (jussi-lind)]

What was the issue with your ISP? I'm asking, because I'm suffering from this same problem and the syslog messages look the same.

[zhiwei (chenzhiwei)]

My ISP use dynamic IP address, IP address changed every 5 minutes.

Not only I can't use vpn, but also I can login many websites, like godaddy and e-bank.