Pedro Izecksohn wrote: >>> I want to understand why someone in my ISP configured the >>> firewall to block ICMP. > >> ISPs will block incoming ICMP packets to help hide the existence of >> their customers. It is a user-friendly feature! > > Every time I send an e-mail, the receiver knows my IP. > Every time I visit some webpage, its webmaster knows my IP.
Not always true (e.g. using the Tor network). > Every time I direct connect to some other IP (P2P), the other guy > knows my IP. > > So what is the advantage of blocking ICMP? To block _incoming_ traffic trying to determine if a computer is turned on at that address. Sure direct connections give away that information, but if you've never been connected to, you can't know that anything is there if all inbound traffic is blocked. > I know that some sysadmins are bad intentioned, but some people want > to legitimate use the blocked connections. Change ISPs then. > If I'ld be a lawmaker I'ld try to pass a law that would force the > sysadmin/owner relation to be contracted on paper, so to leave > unrequested open ports or to install FAT32 would be inexcusable. IMO, Victor's signature applies here "The six most dangerous words: 'There ought to be a law'". You would make one scary lawmaker. I already pay enough in ISP costs, your laws would only increase the cost to people like me (increased red-tape = increased costs). We're getting somewhat off-topic here... -- Thomas Hruska CubicleSoft President Ph: 517-803-4197 *NEW* MyTaskFocus 1.1 Get on task. Stay on task. http://www.CubicleSoft.com/MyTaskFocus/
