我使用的是 16.04 LTS amd64。几天前我的 pptp 连接还好，但从昨天开始就出现故障。连接没有问题，但很快在 3 或 4 分钟内就断开了连接。
这是系统日志（准确指出失败的时刻）：
May 29 11:52:14 ABFORCE pptp[11219]: nm-pptp-service-11187 log[pptp_handle_timer:pptp_ctrl.c:1105]: closing control connection due to missing echo reply
May 29 11:52:14 ABFORCE pptp[11219]: nm-pptp-service-11187 log[ctrlp_rep:pptp_ctrl.c:259]: Sent control packet type is 12 'Call-Clear-Request'
May 29 11:52:14 ABFORCE pptp[11219]: nm-pptp-service-11187 log[pptp_conn_close:pptp_ctrl.c:461]: Closing PPTP connection
May 29 11:52:14 ABFORCE NetworkManager[1017]: Modem hangup
May 29 11:52:14 ABFORCE pptp[11219]: nm-pptp-service-11187 log[ctrlp_rep:pptp_ctrl.c:259]: Sent control packet type is 3 'Stop-Control-Connection-Request'
May 29 11:52:14 ABFORCE NetworkManager[1017]: ** Message: nm-pptp-ppp-plugin: (nm_phasechange): status 8 / phase 'network'
May 29 11:52:14 ABFORCE NetworkManager[1017]: Connect time 4.0 minutes.
May 29 11:52:14 ABFORCE NetworkManager[1017]: Sent 3646742980 bytes, received 2594786 bytes.
May 29 11:52:14 ABFORCE pptp[11219]: nm-pptp-service-11187 log[call_callback:pptp_callmgr.c:84]: Closing connection (call state)
May 29 11:52:14 ABFORCE pppd[11196]: Modem hangup
May 29 11:52:14 ABFORCE pppd[11196]: Connect time 4.0 minutes.
May 29 11:52:14 ABFORCE pppd[11196]: Sent 3646742980 bytes, received 2594786 bytes.
May 29 11:52:14 ABFORCE NetworkManager[1017]: <error> [1464506534.7838] platform-linux: do-add-ip4-route[19: 0.0.0.0/0 50]: failure 100 (Network is down)
May 29 11:52:14 ABFORCE NetworkManager[1017]: <warn> [1464506534.7838] default-route: failed to add default route 0.0.0.0/0 via 0.0.0.0 dev 19 metric 50 mss 0 src vpn with effective metric 50
May 29 11:52:14 ABFORCE NetworkManager[1017]: ** Message: nm-pptp-ppp-plugin: (nm_phasechange): status 5 / phase 'establish'
May 29 11:52:14 ABFORCE NetworkManager[1017]: ** Message: nm-pptp-ppp-plugin: (nm_phasechange): status 11 / phase 'disconnect'
May 29 11:52:14 ABFORCE NetworkManager[1017]: Connection terminated.
May 29 11:52:14 ABFORCE pppd[11196]: Connection terminated.
May 29 11:52:14 ABFORCE NetworkManager[1017]: <error> [1464506534.7852] platform-linux: do-change-link[19]: failure changing link: failure 19 (No such device)
May 29 11:52:14 ABFORCE NetworkManager[1017]: <warn> [1464506534.7852] device (ppp0): failed to disable userspace IPv6LL address handling
May 29 11:52:14 ABFORCE NetworkManager[1017]: ** Message: Terminated ppp daemon with PID 11196.
May 29 11:52:14 ABFORCE NetworkManager[1017]: <error> [1464506534.7856] platform-linux: do-add-ip4-route[19: 0.0.0.0/0 50]: failure 19 (No such device)
May 29 11:52:14 ABFORCE NetworkManager[1017]: <warn> [1464506534.7856] default-route: failed to add default route 0.0.0.0/0 via 0.0.0.0 dev 19 metric 50 mss 0 src vpn with effective metric 50
May 29 11:52:14 ABFORCE NetworkManager[1017]: <info> [1464506534.7893] vpn-connection[0x2a17200,26f48d34-ac2b-4db9-ba9e-ef146551580a,"Sharif VPN",19:(ppp0)]: VPN plugin: state changed: stopping (5)
- 网络管理器 1.1.93
- pptp-linux 1.8.0
- 2.4.7 版
答案1
我遇到了完全相同的问题。我搜索了一整天才明白为什么会发生这种情况。就我而言，根本原因是在系统日志中的一个条目中捕获的： nm-pptp-service-17364 警告[decaps_gre:pptp_gre.c:347]: 短读取 (-1): 消息太长。显然，原因是 WLAN 适配器中的 MTU 设置过大。默认情况下，它设置为自动。
我的方法是将其设置为 1200，它运行良好。
希望这可以帮助，
拉杜