Intensify request packet length checks to only accept the exactly correct packet length

Currently several request packets are checked in such a way that they are accepted and handled if the packet length if larger than the whole request packet should actually be.

For example, if a request packet has a well defined length of 4 byte, currently some service will accept such a request packet, even if the packet headers uses packet length 8.

This is unexpected and the test shall be intensified in such a way that only the exact required packet length is accepted.