a similar problem is shown in the below link from ubnt edgeos . it seems this bug has carried over from the vyatta code.
problem shows up in both 1.1.x and 1.2.0 versions of vyos.
unable to use ipsec over ipv6
Derived from above link, when an ipv6 ipsec site to site vpn is created with a IPv6 VPN endpoint.
vpn {
ipsec {
auto-firewall-nat-exclude disable
esp-group ESP1 {
compression disable
lifetime 3600
mode transport
pfs enable
proposal 1 {
encryption aes128
hash sha1
}
}
ike-group IKE1 {
dead-peer-detection {
action restart
interval 15
timeout 90
}
ikev2-reauth no
key-exchange ikev1
lifetime 28800
proposal 1 {
dh-group 2
encryption aes128
hash sha1
}
}
ipsec-interfaces {
interface eth0
}
site-to-site {
peer yyyy:yyyy:yyyy:yyyy:yyyy:yyyy:yyyy:yyyy {
authentication {
mode pre-shared-secret
pre-shared-secret PassWord
}
default-esp-group ESP1
ike-group IKE1
local-address xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
tunnel 1 {
}
}
}
}
}the following error appears:
commit [ vpn ] [ vpn ipsec site-to-site peer yyyy:yyyy:yyyy:yyyy:yyyy:yyyy:yyyy:yyyy tunnel 1 ] VPN configuration error: IPv4 over IPv6 IPsec is not supported