Dynamic Host Configuration Protocol (DHCP) Snooping is a security feature which filters untrusted DHCP messages, this security feature can protects the devices on the network from associating with an unauthorized DHCP server. When the Dynamic Host Configuration Protocol (DHCP) Snooping feature is enabled on a Cisco Switch , the Cisco Switch builds a table of MAC address, IP address lease time , binding type and interface information. In coming posts I will try to explain to how to enable and configure the Dynamic Host Configuration Protocol (DHCP) snooping security feature in a Cisco Switch.
In which slot shall we install the Supervisor Engine in Cisco 6500 Series Catalyst Switches -Series2
Dear Friends in one of my previous post I did explained in which slot the Supervisor Engine SUP720 to be installed in a Cisco 6500 Series Switches. Now let’s proceed further and figure out in a Cisco Catalyst 6506-E Switch, in a Cisco Catalyst 6506-E Switch the Supervisor Engine SUP720 is either installed in slot 5 or 6.
Dear Friends In my previous post I was talking about the HSRP error generated in Cisco 6513 Switches with a Duplicate IP Address. I did open a TAC case with Cisco Systems. I should first of all salute Cisco for the great support to solve this issue. Cisco TAC Engineer Mr. Pradeep was in constant touch with me in this case to resolve the issue. The best part of their support is the use of technology. Mr. Pradeep initiated a Web Ex meeting with me and spent more than hour to check step by step. He helped me a lot and did learned lot of things from Cisco TAC team, like how to approach the problem and what measures should be taken to trouble shoot any problem. Finally we came to the conclusion there are no bugs or errors in the IOS we are using. There are no problems either in hardware or in the current configuration.I would like to quote the solution provided Mr. Pradeep TAC Engineer, Cisco Systems “Let me summarize this issue. You told me that there is one Trojan affected PC/ Host, which is connected to your access switch. Further, you got some duplicate IP address messages on your core switch. During troubleshooting, I have checked and verified that the Cisco’s Switches are working fine. Their configurations were correct. Generally duplicate IP addresses can be impounded by “broken HSRP links” or “incorrect DHCP pool configuration”, or by misconfiguration of switches or STP. I found that this entire setup is configured correctly. Furthermore, I would like to inform you that Cisco’s IOS cannot resolve Trojan issue on any PC. PC has got its own Operating System, and IOS can work only and only on “Cisco’s device”
So now it’s quite clear if you face this kind of problem make sure the infected PC is removed from the network and make sure it s free from any sort of Trojans or Virus.
Today at 9 a.m. – 5 p.m. Eastern Time there is an IT Security Forum. It’s an online Interactive conference. Cisco is committed to share information you will find indispensable in managing threats.
The following speakers are expected to take part in this online conference.
The IT Security Forum will feature:
- Cisco executives John Stewart, Chief Security Officer, and Marie Hattar, VP, Network Systems and Security Solutions, on virtualization and collaboration
- A review of PCI Data Security Standard v 1.2
- Exclusive data leakage survey results
- 2008 Cisco Annual Security Report preview
- Panel discussions with industry leaders
- Virtual exhibit floor where you can interact with Cisco experts
Please do register to this online conference and make use of this opportunity.
Today, Cisco announced a little something to help clear the way. The world’s largest maker of networking equipment unveiled a new member to its growing family of routers custom-made for the Information Age. Known as the Cisco Aggregation Services Router 9000 (ASR 9000), the company says the machine has six times more capacity and is four times faster than any other router in its class. In fact, the company says, the brawny router is more powerful than any other competing router, period.
Pic Courtesy: Cisco
The ASR 9000 also includes new technologies for proactively managing notoriously challenging video signals. It makes corrections and ensures picture quality for ultra-clear high-definition TV and other video services, Cisco executives say.
For more details check the press release from Cisco.
Don’t panic whenever you see %IP-4-DUPADDR: Duplicate address error log in your Cisco 6500 Switches running HSRP
If you are running HSRP and one of your VLAN is down and the following errors are generated in your Switch don’t panic. All this happens due the Trojans in the network.
Nov 9 07:54:21: %IP-4-DUPADDR: Duplicate address 10.12.0.2 on Vlan106, sourced by 000f.fe0a.1fbc
Nov 9 07:54:52: %IP-4-DUPADDR: Duplicate address 10.12.0.2 on Vlan106, sourced by 000f.fe0a.1fbc
Nov 9 07:55:22: %IP-4-DUPADDR: Duplicate address 10.12.0.2 on Vlan106, sourced by 000f.fe0a.1fbc
Nov 9 07:55:52: %IP-4-DUPADDR: Duplicate address 10.12.0.2 on Vlan106, sourced by 000f.fe0a.1fbc
Nov 9 07:56:11: %SEC-6-IPACCESSLOGS: list 12 permitted 10.0.0.1 256 packets
Nov 9 07:56:22: %IP-4-DUPADDR: Duplicate address 10.12.0.2 on Vlan106, sourced by 000f.fe0a.1fbc
Nov 9 07:56:52: %IP-4-DUPADDR: Duplicate address 10.12.0.1 on Vlan106, sourced by 000f.fe0a.1fbc
Nov 9 07:57:11: %SEC-6-IPACCESSLOGS: list 12 permitted 10.0.0.2 263 packets
Nov 9 07:57:11: %SEC-6-IPACCESSLOGS: list 12 permitted 10.0.0.7 200 packets
Nov 9 07:57:22: %IP-4-DUPADDR: Duplicate address 10.12.0.1 on Vlan106, sourced by 000f.fe0a.1fbc
Nov 9 07:57:52: %IP-4-DUPADDR: Duplicate address 10.12.0.2 on Vlan106, sourced by 000f.fe0a.1fbc
Last week at 3 A.M I received a call from our Help Desk, stating our applications are not running in one our departments. I logged remotely to our Network and try figured out what is problem. Upon carefully looking at the logs in our Cisco 6513 core Switches I figured out a duplicate IP address is created which happens to be the Standby IP address for the Core Switch for HSRP.
I figured out the PC by looking the at mac address generated in the log and closed the network connection for that particular PC and the problem was solved.
If you face similar problems its better to change the HSRP Standby IP address in Core Switches and then try figure out the infected PC. Once the PC is figured out close the network connection and make sure the Trojans are removed. Upon cleaning the infected PC you can reconfigure the HSRP Standby IP address to the previous one.
Once I get the complete solution to fix this problem I will post it.
Dear Friends if you are preparing for CCNA 640-802 certification it would be great to remember the popular applications as well as the TCP/UP ports.
You should at least be aware of some of the applications used to manage and control the network.
In which slot shall we install the Supervisor Engine in Cisco 6500 Series Catalyst Switches -Series1
Dear Friends the Cisco 6500 Series Catalyst Switch comes in different models like Cisco Catalyst 6503-E Switch, Cisco Catalyst 6506-E Switch, Cisco Catalyst 6509-V-E Switch, Cisco Catalyst 6509-E Switch and Cisco Catalyst 6513 Switch. But is there any specific slot assigned in these switches to install the Supervisor Engine SUP720? Yes there are specified slots assigned to install the Supervisor Engine SUP720 in any of the Cisco 6500 Series Switches.
Picture Courtesy: Cisco Systems
Now let’s find out these details,
The Cisco Catalyst 6503-E Switch comes with three slot chassis. In the Cisco Catalyst 6503-E Switch the first two slots are reserved for Supervisor Engine SUP720, if you have one Supervisor Engine SUP720 then you can install the Supervisor Engine SUP720 module either in slot 1 or slot 2.
I will cover these details for other models in my next post.
Tata Communications, a leading provider of the new world of communications, announced the launch of its TelePresence rooms available for public use in the United States and United Kingdom, linking to additional public rooms in Mumbai, Bangalore and Chennai, India. The collaboration between Tata Communications and Cisco is the first managed telepresence service in the world to deliver public and private Cisco TelePresence rooms to companies globally. This new service will allow companies and individuals to use Cisco TelePresence for one-off meetings.Tata Communications is working with Cisco, Taj Hotels owner, the Indian Hotels Company Limited, and the Confederation of India Industry (CII) to offer public telepresence facilities which are available for rent on an hourly basis. The first phase of public rooms was launched in India in July at the Taj Hotels in Mumbai and Bangalore, and CII offices in Bangalore and Chennai. Tata plans to make 100 rooms available globally by the end of 2009.For further information on Tata Communications Telepresence Services visit www.tatacommunications.com/telepresence
The Cisco 360 learning program has been launched. What is it? Its Cisco authorized training for the CCIE Routing and Switching exam. The Cisco 360 learning program is designed to help Network professionals to transform into certified network experts.
The Cisco 360 learning program for CCIE Routing and Switching begins with a four-hour pre-assessment for core routing and switching technologies, allowing organizations to send only qualified network professionals to the program. Once a candidate qualifies, students participate in a 360-degree learning experience that includes skills building, assessments, and mentoring to gain knowledge. Students and their managers can establish milestones and metrics through an online Learning Management System as the individual moves through the program.Students receive training and mentoring from the most proficient, expert-level instructors in the networking business today.
In addition, Cisco uses only authorized Cisco Learning Partners to deploy the new program. Trained and endorsed by Cisco for their competency and ability to deliver unprecedented expert-level training, Cisco Learning Partners are the only organizations to employ Certified Cisco Systems Instructors (CCSIs) and deliver Cisco authorized and approved content. The Cisco 360 Learning Program for CCIE Routing and Switching will be made available November 1, 2008, through select Authorized Cisco Learning Solution Partners and Cisco Learning Partners globally. Access the Cisco Learning Partner Locator here, November 1, 2008 to find an authorized Learning Partner in your region offering the program.