  This paper identifies new class of network steganography methods that utilize
mechanisms to handle oversized packets in IP networks: IP fragmentation, PMTUD
(Path MTU Discovery) and PLPMTUD (Packetization Layer Path MTU Discovery). In
particular, we propose two new steganographic methods and two extensions of
existing ones. We show how IP fragmentation simplifies utilizing steganographic
methods which requires transmitter-receiver synchronization. We present how
mentioned mechanisms can be used to enable hidden communication for both
versions of IP protocol: 4 and 6. Also the detection of the proposed methods is
enclosed in this paper.
