1442byte +20 byte new ip header by ESP in tunnel mode+ 16 Byte ESP Header+2Byte ESP Trailer+xByte pad+12 byte ESP Authentication data=1492+x Byte.(1492+x)%8 == 0,1492%8=4,so the min x is 4,1492+4+14=1510 is the Ethernet frame size. 1438byte +20 byte...