FreeBSD:
Type "make install clean".
Default PREFIX is /usr/local. Configuration files stored in $PREFIX/etc/.
Edit config file. On the gate side copy utcount.sh.default to utcount.sh.

Note, that IPA "maxchunk" variable have no default value. I'm use following /usr/local/etc/ipa.conf: 
global {
	maxchunk = 1G
	update_db_time = 1m
	append_db_time = 30m
}

include {
	file(?) = /usr/local/etc/ipa.users
}

Read ipa.conf(5) man page for details.

Inetd can be used for separate network and application parts:
1. Install utcount on both servers.
2. Choose port (for example, 27777).
2. Add follwing lines to
/etc/services:
utcount         27777/tcp
/etc/inetd.conf:
utcount     stream  tcp nowait      nobody  /usr/local/bin/count_user   utcount
3. Restart inetd. Type "killall -HUP inetd".
4. Adjust "connect" variable in utcount.conf.