我运行的是 Ubuntu 14.04，我可以连接到其他网络上的 VPN，但无法连接到我家里的 VPN。我很确定是我的路由器阻止了连接。我该如何解决这个问题？
来自我的 Syslog 的输出：
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: <info> Starting VPN service 'pptp'...
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: <info> VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 3065
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: <info> VPN service 'pptp' appeared; activating connections
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: <info> VPN plugin state changed: starting (3)
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: <info> VPN connection 'PI' (Connect) reply received.
May 3 16:44:00 jaredSatelliteL650 pppd[3069]: Plugin /usr/lib/pppd/2.4.5/nm-pptp-pppd-plugin.so loaded.
May 3 16:44:00 jaredSatelliteL650 pppd[3069]: pppd 2.4.5 started by root, uid 0
May 3 16:44:00 jaredSatelliteL650 pppd[3069]: Using interface ppp0
May 3 16:44:00 jaredSatelliteL650 pppd[3069]: Connect: ppp0 <--> /dev/pts/0
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
May 3 16:44:00 jaredSatelliteL650 NetworkManager[788]: <warn> /sys/devices/virtual/net/ppp0: couldn't determine device driver; ignoring...
May 3 16:44:00 jaredSatelliteL650 pptp[3073]: nm-pptp-service-3065 log[main:pptp.c:314]: The synchronous pptp option is NOT activated
May 3 16:44:00 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request'
May 3 16:44:00 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply
May 3 16:44:00 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established.
May 3 16:44:01 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request'
May 3 16:44:01 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply.
May 3 16:44:01 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer's call ID 3155).
May 3 16:44:07 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[pptp_read_some:pptp_ctrl.c:544]: read returned zero, peer has closed
May 3 16:44:07 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[callmgr_main:pptp_callmgr.c:258]: Closing connection (shutdown)
May 3 16:44:07 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request'
May 3 16:44:07 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[pptp_read_some:pptp_ctrl.c:544]: read returned zero, peer has closed
May 3 16:44:07 jaredSatelliteL650 pptp[3085]: nm-pptp-service-3065 log[call_callback:pptp_callmgr.c:79]: Closing connection (call state)
May 3 16:44:07 jaredSatelliteL650 pppd[3069]: Modem hangup
May 3 16:44:07 jaredSatelliteL650 pppd[3069]: Connection terminated.
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: <warn> VPN plugin failed: 1
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
May 3 16:44:07 jaredSatelliteL650 pppd[3069]: Exit.
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: <warn> VPN plugin failed: 1
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: <warn> VPN plugin failed: 1
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: <info> VPN plugin state changed: stopped (6)
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: <info> VPN plugin state change reason: 0
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: <info> Policy set 'c:/virus.exe' (wlan0) as default for IPv4 routing and DNS.
May 3 16:44:07 jaredSatelliteL650 NetworkManager[788]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active.
May 3 16:44:12 jaredSatelliteL650 NetworkManager[788]: <info> VPN service 'pptp' disappeared
答案1
/sys/devices/virtual/net/ppp0: couldn't determine device driver; ignoring...
看一下AskUbuntu 上的这个答案，因为你得到的是相同的。正如那里提到的，检查你是否正在使用libgcrypt11=1.5.0-3ubuntu2.2，因为有Launchpad 中已确认的一个错误影响*ubuntu2.1中不存在的版本。
另请参阅这个迷你配置指南，并检查您是否具有正确的身份验证方法并且启用了 MPPE。