操作系统：ubuntu 14.04
我是是按照 http://blog.atime.me/note/l2tp_ipsec_installation_on_ubuntu.html 来配置的
ipsec verify出现错误，google了好久也没找到解决方法。

> root@l:~# ipsec verify Checking if IPsec got installed and started > correctly: > > Version check and ipsec on-path [OK] Openswan > U2.6.42/K3.16.0-23-generic (netkey) See `ipsec --copyright' for > copyright information. Checking for IPsec support in kernel > [OK] NETKEY: Testing XFRM related proc values > ICMP default/send_redirects [OK] > ICMP default/accept_redirects [OK] > XFRM larval drop [OK] Hardware random device check [N/A] Checking > rp_filter [ENABLED] > /proc/sys/net/ipv4/conf/all/rp_filter [ENABLED] > /proc/sys/net/ipv4/conf/default/rp_filter [ENABLED] > /proc/sys/net/ipv4/conf/eth0/rp_filter [ENABLED] > /proc/sys/net/ipv4/conf/lo/rp_filter [ENABLED] > Checking that pluto is running [OK] Pluto > listening for IKE on udp 500 [OK] Pluto listening > for IKE on tcp 500 [NOT IMPLEMENTED] Pluto > listening for IKE/NAT-T on udp 4500 [OK] Pluto listening > for IKE/NAT-T on tcp 4500 [NOT IMPLEMENTED] Pluto > listening for IKE on tcp 10000 (cisco) [NOT IMPLEMENTED] > Checking NAT and MASQUERADEing [TEST > INCOMPLETE] Checking 'ip' command > [OK] Checking 'iptables' command [OK] > > ipsec verify: encountered errors

另外，vpn是可以连上的，也可以访问网络，但是过一会就会出现错误，然后就无法访问网络了

> Nov 7 01:57:17 l pppd[14130]: script /etc/ppp/ip-down, pid 14156 > Nov 7 01:57:17 l pppd[14130]: Terminating on signal 15 Nov 7 > 01:57:17 l pppd[14130]: sending SIGTERM to process 14156 Nov 7 > 01:57:17 l pppd[14130]: Exit. Nov 7 01:57:17 l xl2tpd[13898]: > get_call: can't find call 48693 in tunnel 40624#012 (ref=0/0) Nov 7 > 01:57:21 l xl2tpd[13898]: message repeated 81 times: [ get_call: can't > find call 48693 in tunnel 40624#012 (ref=0 /0)]

希望大家可以帮助我解决这个问题