is the program used by
which is in turn used by
to allow programs which do not or should not run as root to bind to
low-numbered ports in a controlled way. See
It may also be used standalone, i.e. without assistance from
Its standard input should be a TCP/IP socket, and it should be passed
The arguments are the address and port number, respectively, to which
the caller desires that the socket be bound. They should be hex
of exactly the right length (8 and 4 digits, respectively), being
a pairs of hex digits for each byte in the address or port number when
expressed in network byte order.
will not bind to ports 512 and onwards, because programs like
expect these to be used for outgoing connections, so allowing a user
to bind to one of these would open up security hole(s).
will exit with code 0 on success.
will return an appropriate
value as its exit status. If this is not possible it may exit with
status 255 or with an exit status corresponding to
(Function not implemented).
for details of the access control regime implemented by
and this manpage were written by Ian Jackson. They are
by him and released under the GNU General Public Licence; there is NO