Home page logo
/

basics logo Security Basics mailing list archives

RE: How to find a changing IP on ethernet network
From: "Rosenhan, David" <David.Rosenhan () swiftbrands com>
Date: Wed, 3 Mar 2004 08:29:27 -0700

The other cool thing about dot1x on the Cat6k's is if a user does not
authenticate they can be automatically sent to a "guest" VLAN that may
only have access to the internet or whatever you desire (configuring an
ACL on that VLAN interface), pretty cool stuff!

David Rosenhan, CCNP
Information Technology


-----Original Message-----
From: Gary Freeman [mailto:Gary.Freeman () rci rogers com] 
Sent: Tuesday, March 02, 2004 10:54 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




--------------------------------------------------------------
----------
---
Free trial: Astaro Security Linux -- firewall with Spam/Virus 
Protection

Protect your network with the comprehensive security solution that
integrates six applications for ease of use and lower TCO.

Firewall - Virus protection - Spam protection - URL blocking - VPN
- Wireless security.

Download 30-day evaluation at:
http://www.securityfocus.com/sponsor/Astaro_security-basics_040219
--------------------------------------------------------------
----------
----


************************************************************
Please note that our domain name has been changed to: adnoc-dist.ae;
Hence please change the email ID to reflect the new domain name. This 
communication may contain confidential information. If you are not the

intended recipient, then please inform us immediately. Adnoc
Distribution-Tel:02-6771300 Fax:02-6722322 
Email:webmaster () adnoc-dist ae
Website: www.adnoc-dist.ae
 This message was scanned @ Adnoc distribution

************************************************************

************************************************************
Please note that our domain name has been changed to: adnoc-dist.ae;
Hence please change the email ID to reflect the new domain name.
This communication may contain confidential information.
If you are not the intended recipient, then please inform us
immediately.
Adnoc Distribution-Tel:02-6771300 Fax:02-6722322
Email:webmaster () adnoc-dist ae Website: www.adnoc-dist.ae
 This message was scanned @ Adnoc distribution

************************************************************

--------------------------------------------------------------
-------------
--------------------------------------------------------------
--------------




------------------------------------------------------------------------
---
Free 30-day trial: firewall with virus/spam protection, URL filtering,
VPN,
wireless security

Protect your network against hackers, viruses, spam and other risks with
Astaro Security Linux, the comprehensive security solution that combines
six
applications in one software solution for ease of use and lower total
cost
of ownership.

Download your free trial at
http://www.securityfocus.com/sponsor/Astaro_security-basics_040301
------------------------------------------------------------------------
----

------------------------------------------------------------------------
---
Free 30-day trial: firewall with virus/spam protection, URL filtering,
VPN,
wireless security

Protect your network against hackers, viruses, spam and other risks with
Astaro
Security Linux, the comprehensive security solution that combines six
applications in one software solution for ease of use and lower total
cost of
ownership.

Download your free trial at
http://www.securityfocus.com/sponsor/Astaro_security-basics_040301
------------------------------------------------------------------------
----


------------------------------------------------------------------------
---
Free 30-day trial: firewall with virus/spam protection, URL filtering,
VPN,
wireless security

Protect your network against hackers, viruses, spam and other risks with
Astaro
Security Linux, the comprehensive security solution that combines six
applications in one software solution for ease of use and lower total
cost of
ownership.

Download your free trial at
http://www.securityfocus.com/sponsor/Astaro_security-basics_040301
------------------------------------------------------------------------
----


---------------------------------------------------------------------------
Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off
any course! All of our class sizes are guaranteed to be 10 students or less
to facilitate one-on-one interaction with one of our expert instructors.
Attend a course taught by an expert instructor with years of in-the-field
pen testing experience in our state of the art hacking lab. Master the skills
of an Ethical Hacker to better assess the security of your organization.
Visit us at:
http://www.securityfocus.com/sponsor/InfoSecInstitute_security-basics_040303
----------------------------------------------------------------------------


  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]