Mike,
What you need in order for this to work is a separate DSL Modem. It seems that
your DSL modem is built into your firewall, thus not allowing you to separate
it as you need. Although not the best answer, I do believe it is the most
honest one (Unless someone else disagrees).
This is not anything horrible though, you can pick up DSL modems in many retail
stores or online. The modem will convert the RJ11 to RJ45 and from there you
can to into your snort box (A Computer), and from the Snort box to your
firewall. For someone who doesn't do this everyday, I would suggest giving
yourself plenty of time to do in case of mistakes in configuration. I would
also plan out your topology before moving or buying anything.
I hope this helps, let me know if you run into any other troubles.
Adam Botsford
Adam@ProdigyTech.com
www.ProdigyTech.com
www.BashLine.com
On Sat, 25 Mar 2006 10:42:08 +0800
"Mike Gilligan" <mikewgilligan@hotmail.com> wrote:
thanks for the advice on using the Ethernet Tap.
Yes I did consider the tap but remember my Netscreen FW has an integrated
ADSL port so these are not two separate devices that I can put a TAP
between. The telephone cable plugs directly from the wall into my Netscreen
ADSL Firewall and therein lies the problem. Unless there is some way to plug
an RJ11 cable into an ethernet tap which I haven't seen done before.
Mike.
From: James Fryman <jfryman@gmail.com>
To: Mike Gilligan <mikewgilligan@hotmail.com>
CC: security-basics@securityfocus.com
Subject: Re: Snort and ADSL
Date: Fri, 24 Mar 2006 15:36:26 -0500
Mike,
Two options.
1) Get yourself a passive ethernet tap. These can be made cheaply or
bought for some $$. Keep in mind, good taps are not cheap.
2) Grab a cheap dummy hub, and stick it inbetween your Netscreen and
your DSL modem. Stick your snort box in promiscuous mode, and snort
away! I would create yourself a listening Cat5 cable on Internet NIC
segment to prevent any outgoing traffic on your listening port back to
the Internet.
Some good documents exist on the Snort website to get you started:
http://www.snort.org/docs/#deploy
Good luck.
-James
Mike Gilligan wrote:
Hi list.
I have a Netscreen 5GT ADSL FW at my home with two interfaces - inside
and outside. I do have a basic set of IDS sigs on the Netscreen but I
would like to set up a Snort sensor outside the Firewall to look at
unblocked alerts. However, I only have an RJ11 telephone cable to my
ADSL port on the Netscreen and no where to plug in a Snort sensor. I
could plug it in on the inside but I miss a lot of the traffic already
dropped. I know that some SOHO Firewalls like the Linksys ones let you
run Snort on the box itself but this isn't an option for me. Could
anyone suggest a feasible solution?
thanks.
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email : jfryman@gmail.com
Cell : 757.812.3126
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Computer Emergency Response Teams, and Digital Investigations.
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The Norwich University program offers unparalleled Infosec management
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Computer Emergency Response Teams, and Digital Investigations.
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