ISIC is a suite of utilities to exercise the stability of an IP
Stack and its component
stacks (TCP, UDP, ICMP et. al.) It generates piles of pseudo
random packets of the target protocol. The packets be given
tendancies to conform to. Ie 50% of the packets generated can
have IP Options. 25% of the packets can be IP fragments...
But the percentages are arbitrary and most of the packet fields
have a configurable tendancy.
The packets are then sent against the target machine to either
penetrate its firewall rules or find bugs in the IP stack.
ISIC also contains a utility generate raw ether frames to
examine hardware implementations.