Homepage: http://common-lisp.net/project/usocket
License: MIT
USOCKET currently supports 10 CL implementations: ABCL, ACL, ECL, CLISP, CMUCL, LispWorks, MCL, CCL, SBCL, and SCL.
ASDF-install package (obsolete) http://common-lisp.net/project/usocket/releases/usocket-0.5.1.tar.gz
See also: IOlib, another view point for portable networking library in Common Lisp.