Security Basics mailing list archives

RE: How to find a changing IP on ethernet network


From: "Hoang, Binh P,,DMDCWEST" <Hoangbp () osd pentagon mil>
Date: Tue, 2 Mar 2004 13:09:40 -0500

Yeah, 802.1x is cool!
We're in the process of implementing 802.1x for our Wireless LAN (using
Cisco Aironet 1200 Aps). It is a lot more secure than WEP. Another buzzword
that cisco is throwing around is Network Admission Control(NAC), which is
part of their newCisco Self-Defending Network Initiative. Cisco is working
with several anti-virus vendors to develop what they call Cisco Trust Agent
that resides on an endpoint system and communicates with the Cisco network.
What this agent does is, it collects informatin from anti-virus clients and
communicates this info to the Cisco network where access control decisions
are made/enforced. 
As of right now, Cisco has partnership with NAI,Symantec and Trend Micro,
but they said that they will have more partners in the future.

This sounds pretty interesting, doesn't it.


Binh

-----Original Message-----
From: Gary Freeman [mailto:Gary.Freeman () rci rogers com] 
Sent: Tuesday, March 02, 2004 9:54 AM
To: Hoang, Binh P,,DMDCWEST; Khaled; gillettdavid () fhda edu; Bhavani Suresh;
Gideon T. Rasmussen, CISSP, CISM, CFSO, SCSA;
security-basics () securityfocus com
Subject: RE: How to find a changing IP on ethernet network


Hey there,

Port Security is a good Cisco feature for a small LAN but when working with
large networks with roaming users, I would use Port Authentication in
conjunction with Port Security.  Cisco's new buzzword for this is Identity
Based Network Security (IBNS) and uses 802.1x at the client level
(supplicant) to authenticate the user against a RADIUS server. The switch
acts as an authentication proxy and will enable or disable the port based on
the RADIUS response to the MD5 challenge.  The best part of doing dot1x with
Port Security is that the MAC addresses are stored in the user profile
centrally and don't require each switch port to be hard-coded with the MAC
address.

Cheers,

Gary Freeman
Network Security Specialist
RSS-IT Security Team
Rogers Communications Inc.

-----Original Message-----
From: Hoang, Binh P,,DMDCWEST [mailto:Hoangbp () osd pentagon mil] 
Sent: Monday, March 01, 2004 7:02 PM
To: 'Khaled'; gillettdavid () fhda edu; 'Bhavani Suresh'; 'Gideon T. Rasmussen,
CISSP, CISM, CFSO, SCSA'; security-basics () securityfocus com
Subject: RE: How to find a changing IP on ethernet network

I'm sure he meant SNMP trap not SMTP. Anyhow, it's all good!

Binh

-----Original Message-----
From: Khaled [mailto:lists () sonicc net] 
Sent: Monday, March 01, 2004 12:21 PM
To: gillettdavid () fhda edu; 'Bhavani Suresh'; 'Gideon T. Rasmussen, CISSP,
CISM, CFSO, SCSA'; security-basics () securityfocus com
Subject: RE: How to find a changing IP on ethernet network


Hi David, 

If this wasn't the security basics list I would not have replied :) 
The trap you refer to is of course an SNMP trap not SMTP trap (sorry about
being @nal)

Regards,
K.
-----Original Message-----
From: David Gillett [mailto:gillettdavid () fhda edu] 
Sent: Saturday, 28 February 2004 5:18 AM
To: 'Bhavani Suresh'; 'Gideon T. Rasmussen, CISSP, CISM, CFSO, SCSA';
security-basics () securityfocus com
Subject: RE: How to find a changing IP on ethernet network


  If you're using Cisco Catalyst switches, this feature is called "port
security".  Enable it, tell it how many MAC addresses to allow per port, and
whether, when this number 
is exceeded, to issue an SMTP trap to your Network Management 
package, or shut down the switch port.
  Of course, if you're using some other equipment, you need
to find out what features, if any, that equipment offers.

David Gillett


-----Original Message-----
From: Bhavani Suresh [mailto:bhavani.suresh () adnoc-dist co ae]
Sent: Wednesday, February 25, 2004 2:36 AM
To: Gideon T. Rasmussen, CISSP, CISM, CFSO, SCSA; 
security-basics () securityfocus com
Subject: RE: How to find a changing IP on ethernet network



Following up this..i want to know at the network level any software
can bind the MAC Addresses to the ports (and to take current MAC 
Addresses in the network automatically)so that no new ip address can 
be allocated
without the consent of the network admin. This will also 
ensure security
so that non one just plugs in a pc or laptop..

Any idea..

-----Original Message-----
From: Gideon T. Rasmussen, CISSP, CISM, CFSO, SCSA 
[mailto:lists () infostruct net] Sent: Saturday, February 21, 2004 20:12
To: security-basics () securityfocus com
Subject: Re: How to find a changing IP on ethernet network



  Ivan,

This is an interesting situation. Here are a few possible ways to
address it:

1. Send an e-mail to the user community explaining the problem and
asking them to leave their IP address configurations alone.

2. In case you don't know, as the new system boots it announces its IP

address to the network. If another system already has that IP address,

it will reply and the new system will shut down the interface running
the duplicate IP.

a. From the new system, run the arp command (arp -a).

C:\> arp -a

Interface: 192.168.2.100 --- 0x20002
  Internet Address      Physical Address      Type
  192.168.2.1           00-06-25-c0-93-65     dynamic

This will list the IP address and associated MAC (hardware) address
(e.g. 00-06-25-c0-93-65).

b. Now all you need to do is find out which system has that MAC
address:

C:\> ipconfig /all (output abbreviated)

        Physical Address. . . . . . . . . : 00-06-25-c0-93-65

3. You could also use tcpdump or windump
(http://windump.polito.it) to sniff the network traffic for that 
specific IP and view the resulting dump file with Ethereal 
(http://www.ethereal.com). This is a bit advanced for the average 
user.

If you have any additional questions, please do not hesitate to
contact me.

Kind regards,

Gideon

Gideon T. Rasmussen
CISSP, CISM, CFSO, SCSA
Boca Raton, FL
gideon () infostruct net

National Security Awareness Day - September 10, 2004 - Are you aware?

Subject: How to find a changing IP on ethernet network
From: Ivan Andres Hernandez Puga <ivan.hernandez () globalsis com ar>
Date: Fri, 20 Feb 2004 11:54:29 -0300
To: security-basics () securityfocus com

Hello. I have a client with a simple Ethernet network with HUB's
connecting and there is one person that is changing it's IP and 
creating

conflicts. What would you do to track down that person? i mean, to
find who does that?

Thanks!

Ivan Hernandez




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Astaro Security Linux, the comprehensive security solution that combines six
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wireless security

Protect your network against hackers, viruses, spam and other risks with Astaro
Security Linux, the comprehensive security solution that combines six
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