Talk:Promiscuous mode

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Inside each packet is a hardware (MAC) address. When a computer receives a particular packet, it checks the hardware address in it to see if the packet is addressed to it. If not, then the network card normally drops the packet. When in promiscuous mode, the network card doesn't drop the packet, thereby enabling it to read all packets.

I have understand that NIC checks packet against both given IP or MAC depending on protocol. Since MAC address cannot be used to send packets to outside of local network. So if I'm correct, this section of the article is little misleading..? 195.163.176.146 11:33, 18 April 2007 (UTC)

No, network adapters don't check against an IP address. If hosts A and B are not on the same LAN segment, and host A wants to send an IP packet (or a packet for any other routable protocol, such as IPX) to host B, and there's a third host, host C, which is a router that has a network adapter connected to the LAN segment host A is on and another network adapter connected to the LAN segment host B is on, host A will send that packet by sending the packet to host C, which will receive it and then send it to host B. When the packet is sent from host A to host C, the destination IP address is that of host B, but the destination MAC address is of host C; when the packet is sent from host C to host B, the source IP address is that of host A but the source MAC address is that of host C. Guy Harris 17:51, 18 April 2007 (UTC)