环境：
# uname -a
Linux shrimpwagon 3.16.0-4-amd64 #1 SMP Debian 3.16.39-1+deb8u1 (2017-02-22) x86_64 GNU/Linux
我已经安装了：
# apt-get install strongswan xl2tpd
我正在尝试连接到 Meraki VPN。我与 Meraki 技术人员进行了交谈，他说它看起来没有进行身份验证，但没有提供更多详细信息：
# ipsec up L2TP-PSK
generating QUICK_MODE request 2711688330 [ HASH SA No ID ID NAT-OA NAT-OA ]
sending packet: from 10.0.0.4[4500] to 50.123.152.194[4500] (252 bytes)
received packet: from 50.123.152.194[4500] to 10.0.0.4[4500] (68 bytes)
parsed INFORMATIONAL_V1 request 2555305796 [ HASH N(NO_PROP) ]
received NO_PROPOSAL_CHOSEN error notify
establishing connection 'L2TP-PSK' failed
ipsec.conf:
config setup
virtual_private=%v4:10.0.0.0/8
# nat_traversal=yes …