It behaves as a broadcast address. If you want to dig into the details of it all I'd suggest Comer's three volume set on TCP/IP as a good learning tool. {^_^} ----- Original Message ----- From: "Antonio Gallardo" <shrike@xxxxxxxxxxxxxxxxxxxxxxx> > Hello: > > I have a question: > > why I can write: > > ping 0 > ping 0.0 > ping 0.0.0 > ping 0.0.0.0 > > and the return is: > > PING 0.0.0.0 (127.0.0.1) 56(84) bytes of data. > 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.093 ms > 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.131 ms > > > Also, > > working on mozilla if I write: http://0.0/ > > returns the page. > > Can someone also explain why this is valid? I think the address is reserved. > > Best Regards, > > Antonio Gallardo