I am ShadowLord» recieve-only http://iamshadowlord.com Interesting to me Fri, 20 Jan 2012 23:48:50 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Passive Packet Capturing http://iamshadowlord.com/2007/05/passive-packet-capturing.html http://iamshadowlord.com/2007/05/passive-packet-capturing.html#comments Tue, 29 May 2007 18:11:00 +0000 Hans http://iamshadowlord.com/?p=4 User A to User B packet data traffic can be monitored through a HUB by User C using a “receive‑only” Ethernet cable.

On the HUB end of the cable, there is a loop between TX and RX to activate the HUB port. Any traffic through the HUB will now include this port in the broadcasts.

User C taps onto the loop by its receive pins.

Once the connections are made to the HUB, User C will receive all packets that flow through the HUB, but User C will not transmit any packets towards the HUB (no DHCP requests and no ARP requests).

The NIC on User C is in promiscuous mode capturing all incoming packets only.

Using a receive-only Ethernet cable in this configuration allows for the ability to passively capture packets, while not actively being a part of the network.

Network administrators can actively test for devices in promiscuous mode, monitor for DHCP and ARP requests, and review MAC tables to determine the presence of a packet analysis tool.

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