I have a ipsec vpn with a foreign company, this connects my network with their network and they have a different ip subnet. Ipsec is made by a pfsense gateway/firewall.
I'm sure it is well configured, all ipsec params are set and the tunnel looks established.
However foreign colegues cannot connect to my machines, but I have a clue! If I run a ping from my pfsense ipsec interface to foreign ip address magically it starts working and they can connect!!
If they need to connect again after few hours I have to ping them again and so on.... And it works only with ping from ipsec interface.
For me is strange to solve a network problem with a ping. What can be the cause? Where should I focus my search?