/var/log/daemon.log:

# Startup of OpenSwan:

Jun  6 15:54:43 neptun ipsec_setup: Starting Openswan IPsec U2.6.23/K2.6.32-31-generic...
Jun  6 15:54:43 neptun ipsec_setup: Using NETKEY(XFRM) stack
Jun  6 15:54:43 neptun ipsec_setup: ...Openswan IPsec started
Jun  6 15:54:43 neptun ipsec__plutorun: adjusting ipsec.d to /etc/ipsec.d
Jun  6 15:54:43 neptun ipsec__plutorun: 002 added connection description "L2TP-PSK-NAT"
Jun  6 15:54:43 neptun ipsec__plutorun: 002 added connection description "L2TP-PSK-noNAT"
Jun  6 15:54:43 neptun ipsec__plutorun: 002 added connection description "passthrough-for-non-l2tp"
Jun  6 15:54:43 neptun ipsec__plutorun: 003 NAT-Traversal: Trying new style NAT-T
Jun  6 15:54:43 neptun ipsec__plutorun: 003 NAT-Traversal: ESPINUDP(1) setup failed for new style NAT-T family IPv4 (errno=19)
Jun  6 15:54:43 neptun ipsec__plutorun: 003 NAT-Traversal: Trying old style NAT-T

# 1. Login

Jun  6 15:55:45 neptun xl2tpd[32645]: control_finish: Peer requested tunnel 39 twice, ignoring second one.
Jun  6 15:55:45 neptun xl2tpd[32645]: Connection established to 91.57.150.43, 61418.  Local: 54033, Remote: 39 (ref=0/0).  LNS session is 'default'
Jun  6 15:55:45 neptun xl2tpd[32645]: start_pppd: I'm running: 
Jun  6 15:55:45 neptun xl2tpd[32645]: "/usr/sbin/pppd" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "passive" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "nodetach" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "192.168.0.59:192.168.0.60" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "refuse-pap" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "auth" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "require-chap" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "name" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "..." 
Jun  6 15:55:45 neptun xl2tpd[32645]: "debug" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "file" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "/etc/ppp/options.l2tpd" 
Jun  6 15:55:45 neptun xl2tpd[32645]: "/dev/pts/1" 
Jun  6 15:55:45 neptun xl2tpd[32645]: Call established with 91.57.150.43, Local: 39085, Remote: 18245, Serial: 1
Jun  6 15:55:45 neptun NetworkManager:    SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Jun  6 15:55:45 neptun NetworkManager:    SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.

# 1. Logoff

Jun  6 15:56:21 neptun xl2tpd[32645]: result_code_avp: result code out of range (768 0 14).  Ignoring.
Jun  6 15:56:21 neptun xl2tpd[32645]: control_finish: Peer tried to disconnect without specifying result code.
Jun  6 15:56:21 neptun xl2tpd[32645]: result_code_avp: result code out of range (256 0 14).  Ignoring.
Jun  6 15:56:21 neptun xl2tpd[32645]: control_finish: Peer tried to disconnect without specifying result code.
Jun  6 15:56:24 neptun NetworkManager:    SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Jun  6 15:56:24 neptun xl2tpd[32645]: child_handler : pppd exited for call 18245 with code 16
Jun  6 15:56:24 neptun xl2tpd[32645]: call_close: Call 39085 to 91.57.150.43 disconnected
Jun  6 15:56:29 neptun xl2tpd[32645]: Maximum retries exceeded for tunnel 54033.  Closing.
Jun  6 15:56:45 neptun xl2tpd[32645]: Terminating pppd: sending TERM signal to pid 1502
Jun  6 15:56:45 neptun xl2tpd[32645]: pppd 1502 successfully terminated

# 2. Login

Jun  6 15:56:45 neptun xl2tpd[32645]: Connection 39 closed to 91.57.150.43, port 61418 (Timeout)
Jun  6 15:56:50 neptun xl2tpd[32645]: Unable to deliver closing message for tunnel 54033. Destroying anyway.
Jun  6 15:57:20 neptun xl2tpd[32645]: control_finish: Peer requested tunnel 40 twice, ignoring second one.
Jun  6 15:57:25 neptun xl2tpd[32645]: last message repeated 2 times
Jun  6 15:57:25 neptun xl2tpd[32645]: Maximum retries exceeded for tunnel 57069.  Closing.
Jun  6 15:57:29 neptun xl2tpd[32645]: control_finish: Peer requested tunnel 40 twice, ignoring second one.
Jun  6 15:57:29 neptun xl2tpd[32645]: Connection 40 closed to 91.57.150.43, port 56832 (Timeout)
Jun  6 15:57:33 neptun xl2tpd[32645]: control_finish: Peer requested tunnel 40 twice, ignoring second one.
Jun  6 15:57:34 neptun xl2tpd[32645]: Unable to deliver closing message for tunnel 57069. Destroying anyway.
Jun  6 15:57:37 neptun xl2tpd[32645]: control_finish: Peer requested tunnel 40 twice, ignoring second one.