在全新安装的 Kubuntu 15.04 上，我的 VPN 连接无法正常工作，在 14.10 及更早版本上则无法正常工作。我可以通过“连接编辑器”设置连接，但当我想要连接时，它会闪现一个窗口，我可能应该在其中输入密码（但它立即消失了，所以我看不出来）。在说了一会儿正在连接后，它放弃了。Syslog 看起来像这样：
grep NetworkManager /var/log/syslog
Jul 9 15:12:11 hostname NetworkManager[811]: <info> Starting VPN service 'vpnc'...
Jul 9 15:12:11 hostname NetworkManager[811]: <info> VPN service 'vpnc' started (org.freedesktop.NetworkManager.vpnc), PID 2136
Jul 9 15:12:11 hostname NetworkManager[811]: <info> VPN service 'vpnc' appeared; activating connections
Jul 9 15:12:15 hostname ureadahead[307]: ureadahead:NetworkManager_new.1445: Ignored relative path
Jul 9 15:12:15 hostname ureadahead[307]: ureadahead:NetworkManager: Ignored relative path
Jul 9 15:12:15 hostname ureadahead[307]: message repeated 3 times: [ ureadahead:NetworkManager: Ignored relative path]
Jul 9 15:12:15 hostname ureadahead[307]: ureadahead:NetworkManager_new.1490: Ignored relative path
Jul 9 15:12:15 hostname ureadahead[307]: ureadahead:NetworkManager: Ignored relative path
Jul 9 15:12:15 hostname ureadahead[307]: message repeated 2 times: [ ureadahead:NetworkManager: Ignored relative path]
Jul 9 15:14:11 hostname NetworkManager[811]: <error> [1436447651.584396] [vpn-manager/nm-vpn-connection.c:1778] get_secrets_cb(): Failed to request VPN secrets #2: (6) No agents were available for this request.
使用配置中的密码创建连接也无济于事：7 月 9 日 16:46:17 主机名 NetworkManager[811]：[1436453177.020663] [vpn-manager/nm-vpn-connection.c:1778] get_secrets_cb()：无法请求 VPN 机密 #2：（6）没有可用于此请求的代理。
我尝试手动创建一个 conf 文件，似乎部分成功。ifconfig有一个名为的额外项目tun0，我可以使用 URL ping 网站，但无法在浏览器中加载任何网站。这可能表明我的问题类似于这个，但并不完全如此，因为网站无法正常工作是一个很大的限制。这是我在那里所做的：
user@hostname:~$ sudo vpnc-connect /etc/vpnc/my_vpn_config.conf
[sudo] password for user:
Enter IPSec secret for [email protected]:
Enter password for [email protected]:
VPNC started in background (pid: 19663)...
user@hostname:~$ ping askubuntu.com
PING askubuntu.com (122.122.122.122) 56(84) bytes of data.
64 bytes from 122.122.122.122: icmp_seq=1 ttl=59 time=51.1 ms
user@hostname:~$ sudo vpnc-disconnect
Terminating vpnc daemon (pid: 19663)
此连接的系统日志如下所示：
Jul 9 16:15:54 hostname NetworkManager[811]: nm_device_get_device_type: assertion 'NM_IS_DEVICE (self)' failed
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): carrier is OFF
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): new Tun device (driver: 'unknown' ifindex: 6)
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): exported as /org/freedesktop/NetworkManager/Devices/5
Jul 9 16:15:54 hostname NetworkManager[811]: <info> devices added (path: /sys/devices/virtual/net/tun0, iface: tun0)
Jul 9 16:15:54 hostname NetworkManager[811]: <info> device added (path: /sys/devices/virtual/net/tun0, iface: tun0): no ifupdown configuration found.
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): link connected
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: unmanaged -> unavailable (reason 'connection-assumed') [10 20 41]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: unavailable -> disconnected (reason 'connection-assumed') [20 30 41]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) starting connection 'tun0'
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 1 of 5 (Device Prepare) scheduled...
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 1 of 5 (Device Prepare) started...
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: disconnected -> prepare (reason 'none') [30 40 0]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 2 of 5 (Device Configure) scheduled...
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 1 of 5 (Device Prepare) complete.
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 2 of 5 (Device Configure) starting...
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: prepare -> config (reason 'none') [40 50 0]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 2 of 5 (Device Configure) successful.
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 3 of 5 (IP Configure Start) scheduled.
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 2 of 5 (Device Configure) complete.
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 3 of 5 (IP Configure Start) started...
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: config -> ip-config (reason 'none') [50 70 0]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 5 of 5 (IPv4 Configure Commit) scheduled...
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 3 of 5 (IP Configure Start) complete.
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 5 of 5 (IPv4 Commit) started...
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: ip-config -> ip-check (reason 'none') [70 80 0]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) Stage 5 of 5 (IPv4 Commit) complete.
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: ip-check -> secondaries (reason 'none') [80 90 0]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> (tun0): device state change: secondaries -> activated (reason 'none') [90 100 0]
Jul 9 16:15:54 hostname NetworkManager[811]: <info> Activation (tun0) successful, device activated.
Jul 9 16:17:49 hostname NetworkManager[811]: <info> (tun0): device state change: activated -> unmanaged (reason 'removed') [100 10 36]
Jul 9 16:17:49 hostname NetworkManager[811]: <info> (tun0): deactivating device (reason 'removed') [36]
Jul 9 16:17:49 hostname NetworkManager[811]: <info> devices removed (path: /sys/devices/virtual/net/tun0, iface: tun0)
kvpncerror: Timeout while connecting to 123.123.123.123. vpnc connect process will be killed.对网关进行 Ping 操作后，50ms 内返回结果。
我不太确定还能尝试什么。其他选项（pptp、openconnect、openvpn）似乎需要 CA 证书，而我没有，所以我想我只能使用 vpnc 了。希望有人能给我一些建议？
编辑：它似乎是这个错误，尽管那里的修复对我来说不起作用。