Fu,
> Does this means that a multi-homed FreeBSD will start to > route packets on its connected network if its NICs were > in promiscues mode? I don't believe so. I think only the > BPF devices are affected, not ip_input.
if the host is acting as a router, ethernet frames (which are carrying ip packets) will be addressed to the host. so there is no need for the NIC to be in promiscuous mode in order for the host to act as a router. consider that a single host to host connection (over a series of subnets) is made up of a collection of conversations between routers (at the ethernet "layer"). so while there are just two IP addresses involved with your ICMP ping message packet to moon-base-alpha.moon.com, there are dozens of mac addresses involved as the packet hops through various subnets.
see the output of $ man arp and get yourself a copy of TCP/IP Illustrated (W.R. Stevens)
there is some more info for you here http://marc.theaimsgroup.com/?l=ipfilter&m=98944765022022&w=2
but... <<< naming police warning >>>
please don't confuse a multi-homed host with a router. the latter is sometimes also referred to as a gateway.
a multi-homed host does not necessarily route; it is in fact perfectly acceptable for a host to sit on N networks and not pass traffic between then networks. this i think is the proper definition of multi-homed. in this case a multi-homed host NEVER forwards packets between interfaces.
see also http://marc.theaimsgroup.com/?l=ipfilter&m=98927129912996&w=2
a router/routing host, in contrast, accepts packets and does one of three things with them: 1) forwards them out another interface based on a routing table. 2) determines that they are for the "local" host. 3) drops them. this could be due to a routing configuration error on nearby hosts.
jim
Fu Ming wrote:
----- Original Message ----- From: "Remco Post" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, June 06, 2003 4:15 AM Subject: Re: where the ip packet is discarded?
On 6 Jun 2003 09:26:00 +0800 "forge" <[EMAIL PROTECTED]> wrote:
Hello, everyone
I have a hub and several computers connected to it, e.g.
HUB |----B A ---| | |----C
