当我尝试使用网络管理器连接到工作 PPTP VPN 时，它失败了。从系统日志中，我看到有MS-CHAPv2 成功数据包格式不正确在我的连接终止之前。系统日志如下：
Oct 8 14:51:13 reza NetworkManager[7685]: <info> [1602139873.0179] audit: op="connection-activate" uuid="34f9d336-6d43-4ee4-8151-c1d9142f287b" name="VPN 1" pid=24257 uid=1000 result="success"
Oct 8 14:51:13 reza NetworkManager[7685]: <info> [1602139873.0334] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: Started the VPN service, PID 27365
Oct 8 14:51:13 reza NetworkManager[7685]: <info> [1602139873.0439] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: Saw the service appear; activating connection
Oct 8 14:51:13 reza NetworkManager[7685]: <info> [1602139873.0538] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: VPN connection: (ConnectInteractive) reply received
Oct 8 14:51:13 reza NetworkManager[7685]: <info> [1602139873.0565] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: VPN plugin: state changed: starting (3)
Oct 8 14:51:13 reza pppd[27369]: Plugin /usr/lib/pppd/2.4.7/nm-pptp-pppd-plugin.so loaded.
Oct 8 14:51:13 reza NetworkManager[27369]: Plugin /usr/lib/pppd/2.4.7/nm-pptp-pppd-plugin.so loaded.
Oct 8 14:51:13 reza pppd[27369]: pppd 2.4.7 started by root, uid 0
Oct 8 14:51:13 reza pppd[27369]: Using interface ppp0
Oct 8 14:51:13 reza pppd[27369]: Connect: ppp0 <--> /dev/pts/3
Oct 8 14:51:13 reza NetworkManager[27369]: Using interface ppp0
Oct 8 14:51:13 reza NetworkManager[27369]: Connect: ppp0 <--> /dev/pts/3
Oct 8 14:51:13 reza NetworkManager[7685]: <info> [1602139873.0630] manager: (ppp0): new Ppp device (/org/freedesktop/NetworkManager/Devices/42)
Oct 8 14:51:13 reza pptp[27374]: nm-pptp-service-27365 log[main:pptp.c:353]: The synchronous pptp option is NOT activated
Oct 8 14:51:13 reza systemd-udevd[27373]: ethtool: autonegotiation is unset or enabled, the speed and duplex are not writable.
Oct 8 14:51:13 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_rep:pptp_ctrl.c:258]: Sent control packet type is 1 'Start-Control-Connection-Request'
Oct 8 14:51:13 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_disp:pptp_ctrl.c:781]: Received Start Control Connection Reply
Oct 8 14:51:13 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_disp:pptp_ctrl.c:815]: Client connection established.
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_rep:pptp_ctrl.c:258]: Sent control packet type is 7 'Outgoing-Call-Request'
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_disp:pptp_ctrl.c:900]: Received Outgoing Call Reply.
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_disp:pptp_ctrl.c:938]: Outgoing call established (call ID 7775, peer's call ID 38599).
Oct 8 14:51:14 reza gnome-shell[1695]: JS ERROR: TypeError: this._dialog is null#012_onFocusChanged@resource:///org/gnome/shell/ui/closeDialog.js:135:9
Oct 8 14:51:14 reza gnome-shell[1695]: message repeated 1002 times: [ JS ERROR: TypeError: this._dialog is null#012_onFocusChanged@resource:///org/gnome/shell/ui/closeDialog.js:135:9]
Oct 8 14:51:14 reza gnome-shell[1695]: JS ERROR: TypeError: null has no properties#012_onFocusChanged@resource:///org/gnome/shell/ui/closeDialog.js:135:9
Oct 8 14:51:14 reza gnome-shell[1695]: JS ERROR: TypeError: null has no properties#012_onFocusChanged@resource:///org/gnome/shell/ui/closeDialog.js:135:9
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_disp:pptp_ctrl.c:1004]: PPTP_SET_LINK_INFO received from peer_callid 36270
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_disp:pptp_ctrl.c:1006]: send_accm is 00000000, recv_accm is FFFFFFFF
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 warn[ctrlp_disp:pptp_ctrl.c:1011]: Non-zero Async Control Character Maps are not supported!
Oct 8 14:51:14 reza pppd[27369]: MS-CHAPv2 Success packet is badly formed.
Oct 8 14:51:14 reza NetworkManager[27369]: MS-CHAPv2 Success packet is badly formed.
Oct 8 14:51:14 reza NetworkManager[27369]: CHAP authentication failed
Oct 8 14:51:14 reza pppd[27369]: CHAP authentication failed
Oct 8 14:51:14 reza pppd[27369]: Connection terminated.
Oct 8 14:51:14 reza NetworkManager[27369]: Connection terminated.
Oct 8 14:51:14 reza NetworkManager[7685]: <warn> [1602139874.8414] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: VPN plugin: failed: connect-failed (1)
Oct 8 14:51:14 reza NetworkManager[7685]: <info> [1602139874.8415] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: VPN plugin: state changed: stopping (5)
Oct 8 14:51:14 reza NetworkManager[7685]: <info> [1602139874.8415] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: VPN plugin: state changed: stopped (6)
Oct 8 14:51:14 reza NetworkManager[7685]: <info> [1602139874.8445] vpn-connection[0x5579d0f90540,34f9d336-6d43-4ee4-8151-c1d9142f287b,"VPN 1",0]: VPN service disappeared
Oct 8 14:51:14 reza gnome-shell[1695]: Removing a network device that was not added
Oct 8 14:51:14 reza pptp[27374]: nm-pptp-service-27365 warn[decaps_hdlc:pptp_gre.c:226]: short read (-1): Input/output error
Oct 8 14:51:14 reza pppd[27369]: Terminating on signal 15
Oct 8 14:51:14 reza NetworkManager[27369]: Terminating on signal 15
Oct 8 14:51:14 reza pptp[27374]: nm-pptp-service-27365 warn[decaps_hdlc:pptp_gre.c:238]: pppd may have shutdown, see pppd log
Oct 8 14:51:14 reza pppd[27369]: Exit.
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[callmgr_main:pptp_callmgr.c:245]: Closing connection (unhandled)
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[ctrlp_rep:pptp_ctrl.c:258]: Sent control packet type is 12 'Call-Clear-Request'
Oct 8 14:51:14 reza pptp[27385]: nm-pptp-service-27365 log[call_callback:pptp_callmgr.c:84]: Closing connection (call state)
这是我的VPN 设置。我尝试了其他设置，例如仅勾选 MSCHAPv2、将安全设置更改为全部可用（默认）并取消勾选 MPPE，但仍然不起作用。除此之外，我还尝试使用 Windows 操作系统连接到 VPN，令人惊讶的是它可以工作。然后，我尝试将 Windows 计算机上的相同 VPN 设置用于我的 Ubuntu 计算机，但仍然不起作用。
我怀疑是否MS-CHAPv2 成功数据包格式不正确这个问题与我的设置有关吗？还是说这是一个 bug？因为我找到了一个相关链接，但那个链接是针对 l2tp 的，而不是我使用的 pptp。
答案1
请参阅以下 Ubuntu SRU 请求，以反向移植补丁来处理不兼容的 PPP 成功数据包：
点击该页面上的“这个错误是否影响到您？”链接进行投票。投票的人越多，补丁就会越快被移植回来。
它会影响 Linux 上所有基于 PPP 的 VPN 客户端。
该错误实际存在于运行在 Windows Server 上的 VPN 服务器上，但奇怪的是，它并不影响所有 Windows Server，由于某种原因，只有少数服务器受到影响。