Sockets in AF_LOCAL (or AF_UNIX) address space can be referred like
host names in pseudo top-level domain ".af-local".
For example, a socket with address "/tmp/sock" can be referred as
"sock.tmp.af-local", then it is referred in command line options like
"-Psock.tmp.af-local", SERVER=http://sock.tmp.af-local:123", or so.
Port number of socket is ignored in this naming.