[Snort-users] Doing sniffing on interface without ip-address.

Chavez Gutierrez, Freddy fchavez at ...3988...
Fri Nov 2 14:45:02 EST 2001

This is an extract from http://www.snort.org/docs/faq.html :

3.1 --faq-- --snort-- --faq-- --snort-- --faq-- --snort-- --faq--
Q:  How do I setup snort on a 'stealth' interface?

A:  Bring up the interface without an IP address on it. See FAQ 3.2...
A:  Use an ethernet tap, or build your own 'receive-only' ethernet cable.
A:  Anyway, here is the cable I use: 

    LAN Sniffer 
    1 -----\ /-- 1 
    2 ---\ | \-- 2 
    3 ---+-*------- 3 
    4 - | - 4 
    5 - | - 5 
    6 ---*-------- 6 
    7 - - 7 
    8 - - 8 
    Basically, 1 and 2 on the sniffer side are connected, 3 and 6 
    straight through to the LAN. 1 and 2 on the LAN side connect to 3 and 
    6 respectively. This fakes a link on both ends but only allows 
    traffic from the LAN to the sniffer. It also causes the 'incoming' 
    traffic to be sent back to the LAN, so this cable only works well on 
    a hub. You can use it on a switch but you will get ...err... 
    interesting results. Since the switch receives the packets back in on 
    the port it sent them out, the MAC table gets confused and after a 
    short while devices start to drop off the switch. Works like a charm 
    on a hub though. 

3.2 --faq-- --snort-- --faq-- --snort-- --faq-- --snort-- --faq--
Q: How do I run snort on an interface with no IP address?

A: ifconfig ethN up

Freddy Chávez.

-----Mensaje original-----
De: Ashley Thomas [mailto:athomas at ...3539...]
Enviado el: Friday, November 02, 2001 5:15 PM
Para: snort-users at lists.sourceforge.net
Asunto: [Snort-users] Doing sniffing on interface without ip-address.


Where can i get some information how to listen on
a network interface in PROMISCOUS mode without
setting an ip-address on the interface.

Any pointers / hints is welcome.

thanks a lot

Snort-users mailing list
Snort-users at lists.sourceforge.net
Go to this URL to change user options or unsubscribe:
Snort-users list archive:
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.snort.org/pipermail/snort-users/attachments/20011102/0c3949b3/attachment.html>

More information about the Snort-users mailing list