I have Gre tunnel with Ipsec beetween pfsense and cisco. Tunnel is stable and up but I have problems with transfer large files, copying is started, working and suddenly drop while tunnel is up. I read that could be connect with mtu. Ping -l 1472 is working while Ping -l 1473 not. Looks like mtu is 1472. I tried chenge mtu value witj no luck.

Please give me any clue where is a problem.