Using jpcap to forge ARPRequest

Question

when i use JPCap to forge ARP Request , i notice that jpcap is adding a trailer of 18 byte zeros to the tail of the ARP also i am not interested in sending this data. Is there a way to prevent this padding.

Answer 1

The zeros you're seeing are actually padding for the Ethernet frame. Ethernet packets have a minimum payload size of 42 bytes (the reasons have to do with the sender needing to transmit for a certain amount of time to detect collisions). As far as I know there's no way to prevent this, and doing so would be against the Ethernet specification.

Also see question at https://serverfault.com/questions/496324/arp-packet-received-larger-than-packet-sent-why