Re: Snort and ADSL

[Adam Botsford <adam () prodigytech com>]

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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>
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> The Norwich University program offers unparalleled Infosec management 
> education and the case study affords you unmatched consulting experience. 
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EARN A MASTER OF SCIENCE IN INFORMATION ASSURANCE - ONLINE
The Norwich University program offers unparalleled Infosec management 
education and the case study affords you unmatched consulting experience. 
Tailor your education to your own professional goals with degree 
customizations including Emergency Management, Business Continuity Planning, 
Computer Emergency Response Teams, and Digital Investigations. 

http://www.msia.norwich.edu/secfocus
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