我是新手，刚刚开始在 Linux 机器上设置 vpn。
请指出我的配置可能存在哪些问题。
有/var/log/messages：
Sep 16 00:08:07 vm355870 pppd[16789]: pppd 2.4.5 started by root, uid 0
Sep 16 00:08:07 vm355870 pppd[16789]: Using interface ppp0
Sep 16 00:08:07 vm355870 pppd[16789]: Connect: ppp0 <--> /dev/pts/4
Sep 16 00:08:07 vm355870 NetworkManager[639]: <info> [1505509687.4256] manager: (ppp0): new Generic device (/org/freedesktop/NetworkManager/Devices/44)
Sep 16 00:08:07 vm355870 pptp[16790]: anon log[main:pptp.c:333]: The synchronous pptp option is NOT activated
Sep 16 00:08:07 vm355870 pptp[16797]: anon log[ctrlp_rep:pptp_ctrl.c:254]: Sent control packet type is 1 'Start-Control-Connection-Request'
Sep 16 00:08:07 vm355870 pptp[16797]: anon log[ctrlp_disp:pptp_ctrl.c:754]: Received Start Control Connection Reply
Sep 16 00:08:07 vm355870 pptp[16797]: anon log[ctrlp_disp:pptp_ctrl.c:788]: Client connection established.
Sep 16 00:08:08 vm355870 pptp[16797]: anon log[ctrlp_rep:pptp_ctrl.c:254]: Sent control packet type is 7 'Outgoing-Call-Request'
Sep 16 00:08:08 vm355870 pptp[16797]: anon log[ctrlp_disp:pptp_ctrl.c:873]: Received Outgoing Call Reply.
Sep 16 00:08:08 vm355870 pptp[16797]: anon log[ctrlp_disp:pptp_ctrl.c:912]: Outgoing call established (call ID 0, peer's call ID 10169).
Sep 16 00:08:09 vm355870 pptp[16797]: anon log[ctrlp_disp:pptp_ctrl.c:976]: PPTP_SET_LINK_INFO received from peer_callid 0
Sep 16 00:08:09 vm355870 pptp[16797]: anon log[ctrlp_disp:pptp_ctrl.c:979]: send_accm is 00000000, recv_accm is FFFFFFFF
Sep 16 00:08:09 vm355870 pptp[16797]: anon warn[ctrlp_disp:pptp_ctrl.c:982]: Non-zero Async Control Character Maps are not supported!
Sep 16 00:08:10 vm355870 pppd[16789]: CHAP authentication succeeded
Sep 16 00:08:10 vm355870 pppd[16789]: MPPE 128-bit stateless compression enabled
Sep 16 00:08:12 vm355870 pppd[16789]: local IP address 10.213.41.106
Sep 16 00:08:12 vm355870 pppd[16789]: remote IP address 10.213.41.105
Sep 16 00:08:12 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:427]: buffering packet 75 (expecting 15, lost or reordered)
Sep 16 00:08:12 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:427]: buffering packet 76 (expecting 15, lost or reordered)
Sep 16 00:08:12 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:427]: buffering packet 77 (expecting 16, lost or reordered)
Sep 16 00:08:13 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:418]: discarding duplicate or old packet 17 (expecting 79)
Sep 16 00:08:13 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:418]: discarding duplicate or old packet 18 (expecting 79)
Sep 16 00:08:13 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:418]: discarding duplicate or old packet 19 (expecting 81)
Sep 16 00:08:13 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:418]: discarding duplicate or old packet 20 (expecting 84)
Sep 16 00:08:13 vm355870 pptp[16790]: anon log[decaps_gre:pptp_gre.c:418]: discarding duplicate or old packet 21 (expecting 84)