An Infiniband device can have an input port operable to receive a packet and to forward the packet to an output port of the device for onward transmission toward an ultimate destination of the packet. The input port can also be operable to examine at least a header portion of the packet to determine a transmission validity status of the packet and in the event of a negative transmission validity status being determined, to truncate the packet to remove a data payload from the packet including regenerating a checksum field of the packet on the basis of a truncated size of the packet.