vpnc 工作，但网络管理器-vpnc 失败

Question

我正在尝试连接到 vpnc vpn。

我首先创建了一个如下所示的 conf 文件/etc/vpnc/clientvpn.conf：

## generated by pcf2vpnc
IPSec ID mygroupid
IPSec gateway some.ip.add.ress
IPSec secret mygrouppassword

Xauth username myusername
Xauth password myuserpassword
IKE Authmode psk

并且使用sudo vpnc clientvpn效果很好。

现在我想使用网络管理器 vpnc 插件。我创建了一个新的 vpn 设置，并设置了不同的值：

我将高级设置保留为默认值。尝试从 NetworkManager 连接失败，并显示以下日志：

NetworkManager[1155]: <info> Starting VPN service 'vpnc'...
NetworkManager[1155]: <info> VPN service 'vpnc' started (org.freedesktop.NetworkManager.vpnc), PID 5888
NetworkManager[1155]: <info> VPN service 'vpnc' appeared; activating connections
NetworkManager[1155]: <info> VPN plugin state changed: starting (3)
NetworkManager[1155]: <info> VPN connection 'clientvpn' (Connect) reply received.
NetworkManager[1155]:    SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/tun0, iface: tun0)
NetworkManager[1155]:    SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/tun0, iface: tun0): no ifupdown configuration found.
NetworkManager[1155]: <warn> /sys/devices/virtual/net/tun0: couldn't determine device driver; ignoring...
NetworkManager[1155]:    SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/tun0, iface: tun0)
NetworkManager[1155]: <warn> VPN plugin failed: 1
NetworkManager[1155]: <info> VPN plugin state changed: stopped (6)
NetworkManager[1155]: <info> VPN plugin state change reason: 0
NetworkManager[1155]: <info> Policy set 'Connexion filaire 1' (eth0) as default for IPv4 routing and DNS.
NetworkManager[1155]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active.

我不确定是否/sys/devices/virtual/net/tun0: couldn't determine device driver; ignoring...是一个有意义的消息。

为什么nm插件失败，而vpnc工作正常？