/etc/ipsec.conf

  dpddelay=30
  dpdtimeout=120

改为

  dpddelay=5
  dpdtimeout=5

http://linux.die.net/man/5/ipsec.conf
dpddelay Set the delay (in seconds) between Dead Peer Dectection (RFC 3706) keepalives (R_U_THERE, R_U_THERE_ACK) that are sent for this connection。

dpdtimeout Set the length of time (in seconds) we will idle without hearing either an R_U_THERE poll from our peer, or an R_U_THERE_ACK reply.

dpdaction ：When a DPD enabled peer is declared dead, what action should be taken. hold (default) means the eroute will be put into %hold status, while clear means the eroute and SA with both be cleared. restart means the the SA will immediately be renegotiated, and restart_by_peer means that ALL SA‘s to the dead peer will renegotiated.

dpdaction=clear is really only useful on the server of a Road Warrior config.

/etc/ipsec.secrets

/etc/init.d/xl2tpd restart

l2tp pptp相关的一些记录

原文：https://www.cnblogs.com/xiangnan/p/9434389.html