IPsec unidirectional traffic with P1 remote gateway 0.0.0.0
One week ago I decided to setup an ipsec tunnel between a Cisco Router and pfsense 2.4.4_3.
After one week full of testing and debugging turns out that with P1 remote gateway set 0.0.0.0 the isakmp tunnel establish with no problem, but the P2 ipsec tunnel doesn't work: for example if I start a ping from the Cisco I see on Ipsec pfsense interface traffic incoming but pfsense identifies this like an interface error; it doesn't reply end it does not even try to send a ping from its side.
As soon as I change the IP in the remote gateway traffic start flowing and both side see each other.
The problem is that to establish the tunnel I can't set my cisco public ip because it is on internet by a 4G LTE cellular SIM..
Does anybody have any Idea why pfsense doesn't recognize any IPsec traffic with the P1 remote gateway set that way??
I missed an important detail.. Tipology of IPsec is VTI routed