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ipaddr: IP and MAC address manipulation

A library for manipulation of IP and MAC address representations.


  • ounit2-based tests
  • IPv4 and IPv6 support
  • IPv4 and IPv6 CIDR prefix support
  • IPv4 and IPv6 CIDR-scoped address support
  • Ipaddr.V4 and Ipaddr.V4.Prefix modules are Map.OrderedType
  • Ipaddr.V6 and Ipaddr.V6.Prefix modules are Map.OrderedType
  • Ipaddr and Ipaddr.Prefix modules are Map.OrderedType
  • Ipaddr_unix in findlib subpackage ipaddr.unix provides compatibility with the standard library Unix module
  • Ipaddr_top in findlib subpackage provides top-level pretty printers
  • IP address scope classification
  • IPv4-mapped addresses in IPv6 (::ffff:0:0/96) are an embedding of IPv4
  • MAC-48 (Ethernet) address support
  • Macaddr is a Map.OrderedType
  • All types have sexplib serializers/deserializers optionally via the Ipaddr_sexp and Macaddr_sexp libraries.


There are the following opam packages included:

  • ipaddr: the Ipaddr and associated modules
  • ipaddr-sexp
  • ipaddr-cstruct
  • macaddr: the Macaddr and associated modules.
  • macaddr-sexp
  • macaddr-cstruct

There are the following ocamlfind libraries included as part of this repository, included as part of the respective opam packages.

  • ipaddr: The Ipaddr module for IPv4/6 manipulation.
  • Toplevel printers for Ipaddr.
  • ipaddr-cstruct: The Ipaddr_cstruct module
  • macaddr: The Macaddr module for MAC address manipulation.
  • Toplevel printers for Macaddr.
  • macaddr-cstruct: The Macaddr_cstruct module
  • ipaddr-sexp: S-expression converters for Ipaddr.
  • macaddr-sexp: S-expression converters for Macaddr.

Installation and development

The packages are released to the opam-repository. An opam install ipaddr (or any other above mentioned package) will install it. If you want to install the latest development commit, opam pin add ipaddr --dev will do this.

A local build, after a git clone can be done with dune build, a dune runtest compiles and executes the testsuite. If dependencies are missing, opam install (-t) --deps-only . in the cloned directory will install them.

The auto-formatter ocamlformat is used, please execute dune build @fmt --auto-promote before submitting a pull request.