IPSec between Edgrouter and PFSense

With VyOS behind NAT

VyOS conifguration (should be similar to EdgeOS)

set vpn ipsec esp-group esp1 mode tunnel
set vpn ipsec esp-group esp1 pfs enable
set vpn ipsec esp-group esp1 proposal 1 encryption <your choice>
set vpn ipsec esp-group esp1 proposal 1 hash <your choice>
set vpn ipsec ike-group ike1 key-exchange ikev2
set vpn ipsec ike-group ike1 proposal 1 dh-group <your choice>
set vpn ipsec ike-group ike1 proposal 1 encryption <your choice>
set vpn ipsec ike-group ike1 proposal 1 hash <your choice>
set vpn ipsec interfaces interface <the interface used for ipsec>
set vpn ipsec nat-traversal enable
set vpn ipsec site-to-site peer <ip or hostname of your peer> default-esp-group esp1
set vpn ipsec site-to-site peer <ip or hostname of your peer> authentication mode pre-shared-secret
set vpn ipsec site-to-site peer <ip or hostname of your peer> authentication pre-shared-secret <your secret>
set vpn ipsec site-to-site peer <ip or hostname of your peer> authentication id <your public IP>
set vpn ipsec site-to-site peer <ip or hostname of your peer> ike-group ike1
set vpn ipsec site-to-site peer <ip or hostname of your peer> local-address <address that listens for ipsec traffic>
set vpn ipsec site-to-site peer <ip or hostname of your peer> tunnel 1 esp-group esp1
set vpn ipsec site-to-site peer <ip or hostname of your peer> local prefix <local lan>
set vpn ipsec site-to-site peer <ip or hostname of your peer> remote prefix <remote lan>