RE: Network discovery

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To: security-basics@securityfocus.com
Date: Wed, 4 Feb 2004 11:14:10 +0100

Hi,

You can also use HP Openview and select the automatic
Discovery, normally, it is not something that is recommended
To do, but I can assure you that it works, and that you will get
A map with most of your "objects", the only thing is that if you have
To many (network devices), your openview map will soon
Become a mess.

Also HP Openview is not free, so it might be too expensive, for
You budget, nevertheless you can use it for a 1 month trial period.

See you,
Guillaume

-----Mensaje original-----
De: Byron Sonne [mailto:blsonne@rogers.com]
Enviado el: martes, 03 de febrero de 2004 0:59
Para: security-basics@securityfocus.com
Asunto: Re: Network discovery

> I would like to ask all of you, if you have every used a network
> discovery tool? I have a network with more than 5000 PC's and more
> than 70 sites in the country. I would like to create an analysis about
> the network nodes, line between them, speed of the lines etc. Would it
> be possible with a tool to discover the whole internal network, with
> routers, gateways and all the important datas?

No.

You could run a number of utilities/programs which will enumerate alot/most
of the devices on your network and provide quite a bit of information.

It will help you compose a map, but nothing that you can plop on a computer
and run or plug into your network will give you a truly good map unless your
network is configured perfectly, uses common hardware, has a fairly vanilla
config, etc. Even then, I seriously doubt you'll get a complete picture. I
think bad information is worse than no information at all as it can lead you
to make false assumptions. Also, consider the case that if *you* can get all
the information, perhaps a
*cracker* (which is what most people mean when they abuse and misuse the
term 'hacker') could too.

But I digress... there are a number of gotchas you must be aware of. Some of
these gotchas are:

(1) devices that only listen; they don't transmit on the network. Not just
sniffers.
(2) Filtering or Translating proxies of whatever description.
(3) NAT (Network Address Translation)
(4) Firewalls
(5) Custom hardware/software/protocols
(6) Encryption
(7) Temporary power or network outages
(8) Design deficiencies in standard network protocols

Some things that can help out alot are:
(a) Good documentation
(b) Well labelled cabling and devices
(c) A sane overall architecture
(d) Good, knowledgeable people
(e) Good tools. Good starter link: http://www.insecure.org/tools.html
(f) Things like Cisco CDP, etc.

You and your skills are the most important thing of all, so read and learn
as much as possible.

Regards,
Byron Sonne

--
For Good, return Good. For Evil, return Justice.
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We provide Ethical Hacking, Advanced Ethical Hacking, Intrusion Prevention, 
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