Today I am going to talk about the Access Lists and how we can use that access lists in our network. These Access lists are used in many ways. We have different ways to use it and we also have different configurations for different Access Lists.

Before we start with the various access lists, let's talk about what the Access Lists actual are and why they are used. So answer to your question is Access-List is the way to filter the IP packets entering to the network. So with the use of Access-Lists you can permit or deny the IP packets on the base of IPs, Names, protocols and so on and the routing table decide the traffic routing on the basis of the set of rules we authorised.

Below is just a Sample diagram showing using the Access-Lists and has no relevance with any of the configuration used below.

Sample Diagram showing Access-Lists

We have different kinds of Access-lists and I am taking a short note and the configuration part of these access-lists one by one. These access-lists are :

• Standard Access-Lists
• Extended Access-Lists
• IP Named Access-Lists
• Lock and Key Access-Lists
• Reflexive access-Lists
• Context-Based Access Control
• Turbo Access-Lists

Let's Continue reading

Today I am going to discuss on the connectivity of the two datacenter and in the Active-Active state or you can called them as Connecting Multiple Active Datacenter with OTV and Dark Fiber.

First let's talk about the technologies, Cisco OTV is a Overlay Transport Virtualization technology and is used to extend the LAN segments across the datacenter or in other words you can say that extending the Layer 2 traffic over the Layer 3 network.

Note : Cisco OTV supports on Cisco Nexus 7K series switches and is not supported in Cisco Nexus 9K Switches.

Cisco OTV- Overlay Transport Virtualization technology
As I said, that Cisco OTV is the way to extend your layer 2 network across the datacenter via the Layer 3 links. OTV actually works on the MAC routing concept.

MAC and Routing ..What :)

Yes, control plane protocol in Cisco OTV is used to exchange MAC reachability information between network devices providing LAN extension functionality. This is a huge change from Layer 2 switching that traditionally leverages data plane learning, and it is justified by the need to limit flooding of Layer 2 traffic across the transport infrastructure. 

Layer 2 communications between sites Continue reading

Another Cyber-attack shocked Europe as many of the Firms like Airport industries, Banks, Government departments effected by this Petya Cyberattack. It was said that it is the beginning of the attacks and will have many more attacks in near future. Cyber security is one of the most demanding feature now a days who can save you from these cyber attacks.

Fig 1.1- Petya Cyberattack After Wannacry

Experts says, Petya Ransomware attack is just a test and will come up with more worse in the future. So you need to take care about the attacks by applying best security features like Cisco OpenDNS as a first line of security of the big and the other enterprise networks.

Many of the vendors come up with their inputs on the cyberattack where most of the industries across Ukraine, Russia and some part of Europe effected. Most of the firms from Danish and Spanish are effected as well. It may grow towards the Asia and the American region but still no footprints of these attacks.

It is said that ( the effected industries review)- The virus is believed to be ransomware - a piece of malicious software that shuts down a computer system and Continue reading

Today I am going to talk about the basic configurations of OSPF on Cisco routers step by step. OSPF is one of the link state routing protocol and I already wrote some of the articles on OSPF as below:

OSPF Basics- Theory
OSPF point to Multipoint Configuration- Cisco & Juniper
OSPF States
Difference between OSPF Vs RIP routing Protocols

From the above given links, you will able to understand much more about the OSPF. This article is all about the basic configurations on router about the OSPF.

Below is the basic topology of the OSPF which has not any relevance with the configuration part. The topology is just to show you what kind of network you have in the OSPF separated in the areas but with have one process id.

Fig 1.1- Sample OSPF Topology

There is no relevance of the IP addresses uses here with any of the live networks or with any of the enterprise networks.

Lets talk step by step in OSPF

In Step 1, I am talking about how to enable the OSPF routing protocol on Cisco routers by putting the OSPF process id. Make sure you know about the process id, It is similar Continue reading

Today I am going to discuss on the OSPF configuration part, As you already know about the OSPF protocol and the network types in OSPF.

OSPF is a link state routing protocol and i wrote some of the articles on OSPF earlier as well. Please go through that articles to understand more about OSPF protocol

OSPF Basics
OSPF States
OSPF vs RIP protocols
Routing Basics : Distance Vector vs Link State Routing Protocol

Above are some of the articles on OSPF will help you more in the interview preparation.

OSPF Point to Multipoint Networks

Apart from all these today I am going to have sample configurations on OSPF point to multipoint networks.

Here in this article I am going to take a topology of OSPF point to multipoint network and let you know the Continue reading

As in my earlier article i talked about the new launch of the Cisco catalyst 9300 and explain the features of that catalyst switch. Now I am going to talk about the other 2 series which Cisco launches. Cisco understand the requirement of the market and also competing with the other vendors for Next generation networks like SDN where open APIs can be used to stitch third party applications.

Cisco come up with the solution for the campus where they are going to deploy the fabric network on the top of traditional IP network. I will come up with another article where I can explain the architecture of the SD-Access network for the campus network designed by Cisco Systems.

With the launch of Cisco 9300, 9400 and 9500 cisco is running ahead in the field of enterprise network architecture. For Cisco catalyst 9300 please check the below mentioned link

Cisco Catalyst 9300 Switches for Campus

Now let me talk about the other two series of switches launched by Cisco Systems for campus or enterprise network named Cisco catalyst 9400 and 9500 switches.

Cisco Catalyst 9400 Switch:
With the help of Cisco catalyst 9400 switch you will achieve Advanced persistent security threats, Continue reading

Today I am going to talk about the new launch of Cisco. Cisco Launches Catalyst switches in 9000 series and they are not Nexus. If you are confused that it is catalyst switches or Nexus Switches, well It is not Nexus Series it is pure Catalyst switches after Cisco Catalyst 6800 switches.

New Launch : Cisco 9300 series switches and these switches are not Nexus switches in case you are confused.

In addition to all the earlier switches, Cisco take a step ahead from other vendors by adding Cisco 9300, Cisco 9400 and Cisco 9500 Switches in their portfolio. These switches are excellent with the high end capabilities and has many new features added. With the help of these high end switches you can granularly expand your network at core, distribution and access layers and with these switches you will have a leverage of cloud based or Next generation solutions.

Cisco already have the following switches in their portfolio and these switches are

• Cisco 2960 Series
• Cisco 3650 Series
• cisco 3750 Series
• Cisco 3850 Series
• Cisco 4500 Series
• Cisco catalyst 6500 series
• Cisco catalyst 6800 series

With the existing models as shown above, Cisco launches three new catalyst switches series Continue reading

Today I am going to talk about the DHCP Snooping concept in this article. There are lot of queries on DHCP Snooping where people want to understand why it has been used in the enterprise network. Some of the questions i will put here.

What is DHCP Snooping?
What is the different between Trusted and un-trusted hosts, Servers and Ports ?
How DHCP Snooping works ?

These are the basic questions on DHCP Snooping, let me take you guys through it.

Cisco AMP so called as Advance Malware Protection is a term used for Malware file detection technology. AMP will provides you threat intelligence and analytics, point-in-time detection, continuous analysis, and retrospective security of malware files

Today I am going to talk about the Switching topic and that topic is Port Security. Port security is required in the case you want to control the traffic by allowing Specific MAC address entries, which means if the invalid MAC addresses traffic comes, it will be blocked or dropped.

Lets talk about the port security and the modes of port security. So the question is why port security required, may be want to safe from the attacks as well.

Why Port Security is important ?
Well port security is generally used so that you can easily prevent the unwanted MAC address traffic from the external or the internal network.

Port security can be enabled in three different ways are defined as below:

• Protect : In the protected state, switch port will drops packets with unknown source addresses until you remove a sufficient number of secure MAC addresses to drop below the maximum value. 
• Restrict : In the restrict state, switch port will drops packets with unknown source addresses until you remove a sufficient number of secure MAC addresses to drop below the maximum value and causes the SecurityViolation counter to increment
• Shutdown : In the shutdown state, switch port will Continue reading