The \foxnet\ is an implementation of the standard TCP/IP networking protocol
stack using the Standard ML (\sml) language.  \sml\ is a type-safe programming
language with garbage collection, a unique and advanced module system, and
machine-independent semantics.  The \foxnet\ is a user-space implementation of
TCP/IP that is built in \sml\ by composing modular protocol elements; each
element independently implements one of the standard protocols.  One specific
combination of these elements implements the standard TCP/IP stack.  Other
combinations are also possible and can be used to easily and conveniently
build custom, non-standard networking stacks.  This paper describes in detail
the final design and implementation of the \foxnet, including many of the
details that are crucially affected by the choice of \sml\ as the programming
language.