Não consigo manter minha conexão VPN ativa. Estou usando o Ubuntu 14.04 64bit em um Toshiba Protege R30-A-17E.
A conexão VPN simplesmente desaparece após um período de tempo aleatório, não importando se estou usando ou não. Eu tentei algumas coisas que eu descobri aqui ou em alguns fóruns, mas continua caindo. Eu tentei desativar qualquer tipo de compactação, ativou a opção "enviar pacotes de eco do ppp". Eu até tentei usar um adaptador ethernet de rede de maçã USB e ainda assim não tive sorte.
Aqui está o conteúdo do meu syslog (grep'ed by -E "Rede | pptp | pppd").
Sep 23 10:56:35 IVO NetworkManager[765]: <info> Starting VPN service 'pptp'...
Sep 23 10:56:35 IVO NetworkManager[765]: <info> VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 20965
Sep 23 10:56:35 IVO NetworkManager[765]: <info> VPN service 'pptp' appeared; activating connections
Sep 23 10:56:35 IVO NetworkManager[765]: <info> VPN plugin state changed: starting (3)
Sep 23 10:56:35 IVO NetworkManager[765]: <info> VPN connection 'WiseMetering' (Connect) reply received.
Sep 23 10:56:35 IVO pppd[20969]: Plugin /usr/lib/pppd/2.4.5/nm-pptp-pppd-plugin.so loaded.
Sep 23 10:56:35 IVO pppd[20969]: pppd 2.4.5 started by root, uid 0
Sep 23 10:56:35 IVO pppd[20969]: Using interface ppp0
Sep 23 10:56:35 IVO pppd[20969]: Connect: ppp0 <--> /dev/pts/54
Sep 23 10:56:35 IVO NetworkManager[765]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Sep 23 10:56:35 IVO NetworkManager[765]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
Sep 23 10:56:35 IVO NetworkManager[765]: <warn> /sys/devices/virtual/net/ppp0: couldn't determine device driver; ignoring...
Sep 23 10:56:35 IVO pptp[20972]: nm-pptp-service-20965 log[main:pptp.c:314]: The synchronous pptp option is NOT activated
Sep 23 10:56:35 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request'
Sep 23 10:56:35 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply
Sep 23 10:56:35 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established.
Sep 23 10:56:36 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request'
Sep 23 10:56:36 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply.
Sep 23 10:56:36 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer's call ID 11648).
Sep 23 10:56:39 IVO pppd[20969]: CHAP authentication succeeded
Sep 23 10:56:39 IVO pppd[20969]: MPPE 128-bit stateless compression enabled
Sep 23 10:56:41 IVO NetworkManager[765]: <info> (eth0): IP6 addrconf timed out or failed.
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Activation (eth0) Stage 4 of 5 (IPv6 Configure Timeout) scheduled...
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Activation (eth0) Stage 4 of 5 (IPv6 Configure Timeout) started...
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Activation (eth0) Stage 4 of 5 (IPv6 Configure Timeout) complete.
Sep 23 10:56:41 IVO pppd[20969]: local IP address 192.168.200.67
Sep 23 10:56:41 IVO pppd[20969]: remote IP address 192.168.200.1
Sep 23 10:56:41 IVO pppd[20969]: primary DNS address 192.168.200.1
Sep 23 10:56:41 IVO pppd[20969]: secondary DNS address 192.168.200.1
Sep 23 10:56:41 IVO NetworkManager[765]: <info> VPN connection 'WiseMetering' (IP4 Config Get) reply received from old-style plugin.
Sep 23 10:56:41 IVO NetworkManager[765]: <info> VPN Gateway: 194.38.128.63
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Tunnel Device: ppp0
Sep 23 10:56:41 IVO NetworkManager[765]: <info> IPv4 configuration:
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Internal Address: 192.168.200.67
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Internal Prefix: 32
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Internal Point-to-Point Address: 192.168.200.1
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Maximum Segment Size (MSS): 0
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Static Route: 192.168.200.0/24 Next Hop: 192.168.200.0
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Static Route: 192.168.1.0/24 Next Hop: 192.168.1.0
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Forbid Default Route: yes
Sep 23 10:56:41 IVO NetworkManager[765]: <info> Internal DNS: 192.168.200.1
Sep 23 10:56:41 IVO NetworkManager[765]: <info> DNS Domain: '(none)'
Sep 23 10:56:41 IVO NetworkManager[765]: <info> No IPv6 configuration
Sep 23 10:56:42 IVO NetworkManager[765]: <info> VPN connection 'WiseMetering' (IP Config Get) complete.
Sep 23 10:56:42 IVO NetworkManager[765]: <info> Policy set 'Wired connection 1' (eth0) as default for IPv4 routing and DNS.
Sep 23 10:56:42 IVO NetworkManager[765]: <info> Writing DNS information to /sbin/resolvconf
Sep 23 10:56:42 IVO NetworkManager[765]: <info> VPN plugin state changed: started (4)
Sep 23 10:57:36 IVO pptp[20984]: nm-pptp-service-20965 log[logecho:pptp_ctrl.c:677]: Echo Reply received.
Sep 23 11:06:37 IVO pptp[20984]: message repeated 9 times: [ nm-pptp-service-20965 log[logecho:pptp_ctrl.c:677]: Echo Reply received.]
Sep 23 11:06:37 IVO pptp[20984]: nm-pptp-service-20965 log[logecho:pptp_ctrl.c:679]: no more Echo Reply/Request packets will be reported.
Sep 23 11:17:37 IVO pptp[20984]: nm-pptp-service-20965 log[pptp_handle_timer:pptp_ctrl.c:1050]: closing control connection due to missing echo reply
Sep 23 11:17:37 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request'
Sep 23 11:17:37 IVO pptp[20984]: nm-pptp-service-20965 log[pptp_conn_close:pptp_ctrl.c:430]: Closing PPTP connection
Sep 23 11:17:37 IVO pptp[20984]: nm-pptp-service-20965 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 3 'Stop-Control-Connection-Request'
Sep 23 11:17:37 IVO pptp[20984]: nm-pptp-service-20965 log[call_callback:pptp_callmgr.c:79]: Closing connection (call state)
Sep 23 11:17:37 IVO pppd[20969]: Modem hangup
Sep 23 11:17:37 IVO pppd[20969]: Connect time 21.0 minutes.
Sep 23 11:17:37 IVO pppd[20969]: Sent 10793 bytes, received 9913 bytes.
Sep 23 11:17:37 IVO pppd[20969]: MPPE disabled
Sep 23 11:17:37 IVO pppd[20969]: Connection terminated.
Sep 23 11:17:37 IVO NetworkManager[765]: <info> VPN plugin state changed: stopping (5)
Sep 23 11:17:37 IVO NetworkManager[765]: <info> VPN plugin state changed: stopped (6)
Sep 23 11:17:37 IVO NetworkManager[765]: <info> VPN plugin state change reason: 0
Sep 23 11:17:37 IVO pppd[20969]: Exit.
Sep 23 11:17:38 IVO NetworkManager[765]: <info> Policy set 'Wired connection 1' (eth0) as default for IPv4 routing and DNS.
Sep 23 11:17:38 IVO NetworkManager[765]: <info> Writing DNS information to /sbin/resolvconf
Sep 23 11:17:38 IVO NetworkManager[765]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active.
Sep 23 11:17:38 IVO NetworkManager[765]: <warn> (45) failed to find interface name for index
Sep 23 11:17:38 IVO NetworkManager[765]: nm_system_iface_flush_routes: assertion 'iface != NULL' failed
Sep 23 11:17:38 IVO NetworkManager[765]: <warn> (45) failed to find interface name for index
Sep 23 11:17:38 IVO NetworkManager[765]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Sep 23 11:17:43 IVO NetworkManager[765]: <info> VPN service 'pptp' disappeared
Alguém tem uma pista do que está acontecendo aqui?
EDITAR
Eu tenho dois laptops diferentes, ambos rodando o Ubuntu 14.04 64bits (na verdade, um deles está rodando o Xubuntu, mas é basicamente o mesmo).
Ambos os laptops mostram exatamente o mesmo comportamento com a VPN desconectando aleatoriamente após registrar algo como "fechar a conexão de controle devido a falta de resposta de eco" ao syslog.
Eu também tenho um pequeno netbook no qual eu instalei #! 11 (que ainda roda o kernel 3.2 btw). Com a mesma configuração exata, a VPN aqui não foi desconectada por pouco mais de 10 horas e a única razão pela qual ela se desconectou da VPN foi porque eu disse a ela.
Então, isso pode ser um problema do Ubuntu 14.04? ou um problema no kernel? ou um problema de versão lib?
Provavelmente, o servidor VPN não suporta alguns recursos de compactação. Se o servidor for baseado em Windows, tente desabilitar o envio de pacotes de Eco PPP, também desabilitar a compactação BSD, desinflar compactação e compactação de cabeçalho TCP para solucionar o problema. Se o problema persistir, o erro de DNS poderá ser o culpado.