hostaccess# strace proftpd -n  2>&1 | grep bind
setgroups(1, [65534]my.host.name - Failed binding to X.X.X.X, port 28: Address already in use
hostaccess# strace nc -l X.X.X.X 28  2>&1 | grep bind
bind(3, {sa_family=AF_INET, sin_port=htons(28), sin_addr=inet_addr("X.X.X.X")}, 16) = 0
^C
hostaccess#