$ ipsec up example
initiating Main Mode IKE_SA example[2] to 203.0.113.2
generating ID_PROT request 0 [ SA V V V V ]
sending packet: from 203.0.113.1[500] to 203.0.113.2[500] (248 bytes)
received packet: from 203.0.113.2[500] to 203.0.113.1[500] (200 bytes)
parsed ID_PROT response 0 [ SA V V V V V V ]
received NAT-T (RFC 3947) vendor ID
received draft-ietf-ipsec-nat-t-ike-03 vendor ID
received draft-ietf-ipsec-nat-t-ike-02\n vendor ID
received draft-ietf-ipsec-nat-t-ike-02 vendor ID
received draft-ietf-ipsec-nat-t-ike-00 vendor ID
received DPD vendor ID
generating ID_PROT request 0 [ KE No NAT-D NAT-D ]
sending packet: from 203.0.113.1[500] to 203.0.113.2[500] (308 bytes)
received packet: from 203.0.113.2[500] to 203.0.113.1[500] (292 bytes)
parsed ID_PROT response 0 [ KE No NAT-D NAT-D ]
local host is behind NAT, sending keep alives
generating ID_PROT request 0 [ ID HASH ]
sending packet: from 203.0.113.1[4500] to 203.0.113.2[4500] (68 bytes)
received packet: from 203.0.113.2[4500] to 203.0.113.1[4500] (68 bytes)
parsed ID_PROT response 0 [ ID HASH ]
IKE_SA example[2] established between 203.0.113.1[203.0.113.1]...203.0.113.2[203.0.113.2]
scheduling reauthentication in 10082s
maximum IKE_SA lifetime 10622s
generating QUICK_MODE request 2118468074 [ HASH SA No ID ID NAT-OA NAT-OA ]
sending packet: from 203.0.113.1[4500] to 203.0.113.2[4500] (244 bytes)
received packet: from 203.0.113.2[4500] to 203.0.113.1[4500] (172 bytes)
parsed QUICK_MODE request 983053170 [ HASH SA No ID ID NAT-OA NAT-OA ]
generating QUICK_MODE response 983053170 [ HASH SA No ID ID NAT-OA NAT-OA ]
sending packet: from 203.0.113.1[4500] to 203.0.113.2[4500] (196 bytes)
received packet: from 203.0.113.2[4500] to 203.0.113.1[4500] (172 bytes)
parsed QUICK_MODE response 2118468074 [ HASH SA No ID ID NAT-OA NAT-OA ]
received netlink error: Function not implemented (89)
unable to add SAD entry with SPI c40bb430
received netlink error: Function not implemented (89)
unable to add SAD entry with SPI a6a62a78
unable to install inbound and outbound IPsec SA (SAD) in kernel
establishing connection 'example' failed