where I run

timed -n test-net

to force timed to only bind to a specific network I get the
following error

timed: no network usable

Since my /etc/networks file has the correct infos in it. I
dig into the source code... The problem was nail down to the
following lines of the timed source code

timed.c line 393

                nt->net = htonl(nt->net);

This seems to do nothing (nt->net doesn't change),
which suprised me since I'm on a little endian architecture
(i686).

So I wrote the following test program :

#include <netdb.h>
#include <stdio.h>
#include <netinet/in.h>

int
main ( int argc, char *argv[])
{
        struct netent *net;
        unsigned long haddr,naddr;

        if ( argc != 2 ) {
                fprintf( stderr, "usage: test <net>\n" );
                exit(2);
        }

        net = getnetbyname( argv[1] );
        if ( !net) {
                fprintf( stderr, "no such network: %s\n",
argv[1] );
                exit(1);
        }

        haddr = net->n_net;
        naddr = htonl(haddr);

        printf( "Network in host byte order: %lu\n", haddr);
        printf( "Network in network byte order: %lu\n",
naddr);

        exit(0);
}

Which when is compiled either as gcc  -O2 -o test test.c or
gcc -o test test.c gives the same uncomprehensible result.
(/etc/networks contains)

192.168.250.0   test-net

$ ./test test-net
Network in host byte order: 4294967295
Network in network byte order: 4294967295