in reply to Net::RawIP failing in some case

ifconfig eth2 mtu 65535

The maximum transmission unit for an Ethernet is only 1500. I think we can't increase it more than 1500.

Ethernet can't deal with IP datagrams greater than 1,500 bytes in size.

If you want you can refer the following link

Guide
--Lakshmanan G.

Your Attempt May Fail, But Never Fail To Make An Attempt