在升级到testing之前，vpn还是好用的。不确定是不是升级的原因。求解。
我用的network-manager-pptp-gnome建立的vpn连接。
连接不上还是特别慢？
若无法建立连接，看一下日志 (用 sudo journalctl -f 滚动监视)
若特别慢，看看是不是老问题 forum.ubuntu.org.cn/viewtopic.php?f=165&t=473811
-- Logs begin at Tue 2016-04-12 19:01:04 CST. --
Apr 15 10:12:19 debian NetworkManager[634]: Plugin /usr/lib/pppd/2.4.7/nm-pptp-pppd-plugin.so loaded.
Apr 15 10:12:19 debian NetworkManager[634]: ** Message: nm-pptp-ppp-plugin: (plugin_init): initializing
Apr 15 10:12:19 debian NetworkManager[634]: (process:15228): GLib-GIO-CRITICAL **: g_dbus_proxy_new_sync: assertion 'g_variant_is_object_path (object_path)' failed
Apr 15 10:12:19 debian NetworkManager[634]: ** (nm-pptp-service:15220): WARNING **: pppd died with signal 11
Apr 15 10:12:19 debian kernel: pppd[15228]: segfault at 8 ip 00007fa93f49db1c sp 00007fffb099e000 error 4 in nm-pptp-pppd-plugin.so[7fa93f49c000+3000]
Apr 15 10:12:19 debian NetworkManager[634]: <warn> [1460686339.2094] vpn-connection[0x1f075c0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: failed: connect-failed (1)
Apr 15 10:12:19 debian NetworkManager[634]: <info> [1460686339.2096] vpn-connection[0x1f075c0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: state changed: stopping (5)
Apr 15 10:12:19 debian NetworkManager[634]: <info> [1460686339.2108] vpn-connection[0x1f075c0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN service disappeared
Apr 15 10:12:29 debian sudo[15232]: yangdawei : TTY=pts/0 ; PWD=/home/yangdawei ; USER=root ; COMMAND=/bin/journalctl -f
Apr 15 10:12:29 debian sudo[15232]: pam_unix(sudo:session): session opened for user root by yangdawei(uid=0)
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.4726] audit: op="connection-activate" uuid="e230c951-3def-45d4-b56f-096f4312bba2" name="VPN connection 1" pid=15929 uid=1000 result="success"
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.4794] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: Started the VPN service, PID 15240
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.4886] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: Saw the service appear; activating connection
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.4916] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: state changed: init (1)
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.5437] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN connection: (ConnectInteractive) reply received
Apr 15 10:12:38 debian NetworkManager[634]: ** Message: pppd started with pid 15248
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.5535] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: state changed: starting (3)
Apr 15 10:12:38 debian pppd[15248]: Plugin /usr/lib/pppd/2.4.7/nm-pptp-pppd-plugin.so loaded.
Apr 15 10:12:38 debian NetworkManager[634]: Plugin /usr/lib/pppd/2.4.7/nm-pptp-pppd-plugin.so loaded.
Apr 15 10:12:38 debian NetworkManager[634]: ** Message: nm-pptp-ppp-plugin: (plugin_init): initializing
Apr 15 10:12:38 debian NetworkManager[634]: (process:15248): GLib-GIO-CRITICAL **: g_dbus_proxy_new_sync: assertion 'g_variant_is_object_path (object_path)' failed
Apr 15 10:12:38 debian NetworkManager[634]: ** (nm-pptp-service:15240): WARNING **: pppd died with signal 11
Apr 15 10:12:38 debian kernel: pppd[15248]: segfault at 8 ip 00007f3b6072bb1c sp 00007ffd0ed7af80 error 4 in nm-pptp-pppd-plugin.so[7f3b6072a000+3000]
Apr 15 10:12:38 debian NetworkManager[634]: <warn> [1460686358.5611] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: failed: connect-failed (1)
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.5615] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: state changed: stopping (5)
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.5615] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: state changed: stopped (6)
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.5624] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN plugin: state change reason: unknown (0)
Apr 15 10:12:38 debian NetworkManager[634]: <info> [1460686358.5635] vpn-connection[0x1f077b0,e230c951-3def-45d4-b56f-096f4312bba2,"VPN connection 1",0]: VPN service disappeared该 bug 已经被报告 bugs.debian.org/cgi-bin/bugrepo … bug=820295
该问题影响 network-manager-pptp/1.1.93-1, network-manager-pptp/1.1.92-1
可以到 snapshot.debian.org 找一个 早于 1.1.92-1 的 network-manager-pptp-gnome 看能否手动安装 退回去
或临时手动使用 pptp 客户端
[code]# pptpsetup --create tunnel --server host.com --username alice
–password foo --encrypt
pon tunnel
ip route add default dev ppp0[/code]
参考：
bugs.debian.org/cgi-bin/bugrepo … bug=820295
note.cncore.com/index.php?p=/dis … 5%8F%B7/p1
手动建立pptp连接过程：
- 安装pptpsetup
- 建立vpn帐号并启动
tunnel是连接名称，其余为服务器地址或域名、用户名、密码。
若使用ifconfig -a 查看网络，会出现一个ppp0的网卡。
- 建立新的路由
sudo ip route del default
sudo ip route add default dev ppp0
现在即可使用vpn上网了。
我现在遇到的问题是，上网极慢。按原来的方式，将mtu改为1300后还是很慢。
不是说GFW几乎已经吃透了现有的VPN么，难道你们还能用？
我买vps搭ss的时候教程上还专门提醒，不要开vpn，会死，只搭ss
在安卓和Win上都还能用。只是目前在Linux上连接后速度慢。
参考：
bugs.launchpad.net/ubuntu/+source/network-manager-pptp/+bug/1568336
wget https://launchpad.net/ubuntu/+source/network-manager-pptp/1.1.93-1ubuntu1/+build/9574101/+files/network-manager-pptp_1.1.93-1ubuntu1_amd64.deb
wget https://launchpad.net/ubuntu/+source/network-manager-pptp/1.1.93-1ubuntu1/+build/9574101/+files/network-manager-pptp-gnome_1.1.93-1ubuntu1_amd64.deb
dpkg -i network-manager*.deb
rm network-manager*.deb
尝试了一下，问题果然解决了。
同求，如何建立一个vpn链接，之前有软件在win上用的，但是官网不支持deb的格式