我正在运行 Ubuntu 14.04，我正在尝试设置一个点对点虚拟专用网络在我和服务器之间。我正在network-manager为此使用。
现在，当我使用以太网，而无线上网我的笔记本电脑不知道如何访问服务器（尽管可以ping按预期工作）：
15:50:35 NetworkManager[16692]: <info> Starting VPN service 'pptp'...
15:50:35 NetworkManager[16692]: <info> VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 28057
15:50:35 NetworkManager[16692]: <info> VPN service 'pptp' appeared; activating connections
15:50:35 NetworkManager[16692]: <info> VPN plugin state changed: starting (3)
15:50:40 NetworkManager[16692]: <info> VPN connection 'pacage' (Connect) reply received.
15:50:40 pppd[28069]: Plugin /usr/lib/pppd/2.4.5/nm-pptp-pppd-plugin.so loaded.
15:50:40 pppd[28069]: pppd 2.4.5 started by root, uid 0
15:50:40 pppd[28069]: Using interface ppp0
15:50:40 pppd[28069]: Connect: ppp0 <--> /dev/pts/23
15:50:40 NetworkManager[16692]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
15:50:40 NetworkManager[16692]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
15:50:40 NetworkManager[16692]: <warn> /sys/devices/virtual/net/ppp0: couldn't determine device driver; ignoring...
15:50:40 pptp[28073]: nm-pptp-service-28057 log[main:pptp.c:314]: The synchronous pptp option is NOT activated
15:50:40 pptp[28075]: nm-pptp-service-28057 warn[open_inetsock:pptp_callmgr.c:329]: connect: No route to host
15:50:40 pptp[28075]: nm-pptp-service-28057 fatal[callmgr_main:pptp_callmgr.c:127]: Could not open control connection to x.x.x.x
15:50:40 pptp[28073]: nm-pptp-service-28057 fatal[open_callmgr:pptp.c:487]: Call manager exited with error 256
15:50:40 pppd[28069]: Modem hangup
15:50:40 pppd[28069]: Connection terminated.
15:50:40 NetworkManager[16692]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
15:50:40 NetworkManager[16692]: <warn> VPN plugin failed: 1
15:50:40 pppd[28069]: Exit.
我在这里遗漏了什么？
答案1
问题可能仅仅是 GRE 数据包没有通过。
要解决此问题，请确保 Wifi 路由器或防火墙允许 GRE 协议 47（您需要在知道如何处理 GRE 数据包的路由器上找到并启用“PPTP 直通”功能）。事实上，端口 1723 和 GRE 协议都应该打开/启用，才能使用 PPTP 建立 VPN 连接。
希望它可以解决问题。