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Policy Based Routing

Policy Based Routing 150 150 tiptechnoloy_0sppo6

Policy based routing

This is more like a filter for networks. It has 3 basic steps

ACL to define interesting traffic
Routemap to refer to the ACL (If/Then statement)
Apply route Map to ingress interface

Normal traffic outward flow
R1 – R3 – R5 – R4 – R7
Return path
R7 – R4 – R5 – R3 – R1

Apply Route-Map on R4 to change the return Path
Return path

R7 – R4 – R3 – R1

R4# show access list

#access-list 100 permit ip host any
#route-map PBR
#match IP address 100 // looking for Access list that matches acl 100. The “Match” is the “IF” portion
#set ip next-hop //The “Set” is the “Then” portion

//Please Note: If you do not specify a match statement, and only specify Set, it will match every other route to the PBR. If we dont set an alternative match statement, it will use the dedault route table.
//to check the route path

R7# traceroute
R7# traceroute source

//to change the path, go to R4 ingress interface to apply the route map

R4# int se1/1.478
#ip policy route-map PBR

Verify the PBR you just applied

R4# sh ip policy
R4# Debug ip policy

// Lets go to R7
R7# traceroute
//Traffic flows normally as it is not coming from but from
R7# traceroute source
//Now you see the traffic path changes acording to PBR

Reference …From Keith Barker’s CBT.

Blog Post Title

Blog Post Title 150 150 tiptechnoloy_0sppo6

What goes into a blog post? Helpful, industry-specific content that: 1) gives readers a useful takeaway, and 2) shows you’re an industry expert.

Use your company’s blog posts to opine on current industry topics, humanize your company, and show how your products and services can help people.

Get Started With Cisco DevNet

Get Started With Cisco DevNet 150 150 tiptechnoloy_0sppo6

Start by Building your lab your Lab on your PC.

Cisco DevNet

Source control systems like git or Subversion are a core part of the software development workflow.

Examples of shells include:
bash (or “Bourne-again shell”) is a common shell Mac, Linux and other “Unix-like” operating systems
cmd.exe is the native command line interpreter for Windows systems
PowerShell is a combination shell and scripting framework from Microsoft that has recently become open source and cross platform

git has become one of the most commonly used source control systems in the development
‘repos’ – Cisco DevNet are hosted in git repositories
leverage the git-bash shell that is included with git for Windows.

Node.js is a JavaScript runtime that is very popular for developers because of the JavaScript foundation providing a consistent language across web (sometimes called “frontend”) and application (sometimes called “backend”) development.
VS Code is ideal for JavaScript development, and has powerful and complete language support for Python, .NET, Java and other languages as well.
Find out more at

Postman is a powerful REST API client that provides a set of capabilities for testing, exploring, and writing REST APIs.
ngrok is one of several possible tools that aims to solve this problem for developers. It is an application you’ll run on your environment, and it builds a connection path from the public internet to your local workstation

if you do not have AnyConnect, the open source alternative OpenConnect can be used.

Docker is not the only application container engine, and wasn’t even the first. But it is definitely the most popular one in use today,

Installation and setup

Navigate to
Click the link for “Windows”
Consider changing the default text editor for Git to another option, if you have one available. For example, Notepad++

Open git-bash
within the terminal, run
git –version
Attempt to clone a repository from GitHub.
git clone

Change to the hello_network directory that you cloned down in the last step.
cd hello_network

included in the repository is a bash shell script called, run it to verify you have a functioning bash shell.
# Expected Output
Hello Network!

Installing Python 3

Navigate to

Click the link “Latest Python 3 Release – Python 3.6.9”.
In the list, download “Windows x86-64 executable installer” (If you are on 32 bit Windows download the x86 version).
Run the downloaded installation file taking the defaults with the following suggestions.
On the first page “Install Python 3.6.9” screen, check the box to “Add Python 3.6 to PATH” at the bottom of the screen.

Verify Python installation
Note: If the following verifications do not work as expected, restart your computer to ensure the updated “PATH” variables are fully applied.

Open a git-bash terminal.
Verify Python 3 was correctly installed. (The py application is the “Python launcher for Windows” that provides an easy method on Windows to identify Python versions)
py -3 -V
# Expected Output
Python 3.6.9

Check the version set as the “Default Python Version”. (The default version is the version of Python that is executed when you enter python).
python -V
# Expected Output
Python 3.6.9

Note: To open an interactive Python interpreter you can typically just use the command python at the command prompt. Within git-bash you need to use the command python -i to explicitly start the interactive interpreter.

Python virtual environments
Before leaving the Python setup, you need to know how to create a Python virtual environment. Python virtual environments are a method of creating isolated “environments” where specific versions of Python can be installed along with independent sets of libraries and dependencies.

Virtual environment usage is very common and is recommended practice when working in Python, and most DevNet labs encourage you to create and work within virtual environments.

Create a Python 3 virtual environment using the venv module included with Python 3.

py -3 -m venv py3-venv
Now “activate” the environment. Look for the name of the virtual environment to be enclosed in parenthesis after activation.

source py3-venv/Scripts/activate
# Expected Output
IEUser@IE11Win10 MINGW64 ~/code
Now verify that python is now linked to Python 3

python -V
Python 3.6.9

Deactivate the virtual environment.


Installing Node
Navigate to and download the “Windows Installer.”
Run the downloaded installer taking the defaults.

Open a git-bash terminal.

Check the installed node version.

node -v
# Expected Output

Step 5: Text Editors and IDE
You probably don’t need two different IDEs…but you might enjoy taking Atom and Visual Studio Code for a side-by-side test run, so we’ve included installation instructions for each

Navigate to

The site should detect your OS and offer you an appropriate download link

Run the downloaded installer taking the defaults

Once installation finishes, Atom should open and display the interface

Select “Yes, Always” to the question about registering the atom:// URI handler

Visual Studio Code
Navigate to

The site should detect your OS and offer you an appropriate download link

Run the downloaded installer taking the defaults

Once installation finishes, open VS Code to display the main interface

In the upper left, select the Extensions view, search for “python” and install the top hit, i.e. the “Python” extension (by Microsoft)

Step 6: Development Tools and Clients
Navigate to
Click the download link for “Windows”. (If you are using a 32 bit version of Windows, be sure to change the option.)
Run the downloaded installer taking the defaults.

Once the installation completes, Postman will open and allow you to sign-up or sign-in. You do NOT need to sign in to use Postman, you can simply click the link “Take me straight to the app. I’ll create an account another time.” to bypass login.

Test that you can make REST API calls with Postman with this fun “Dad Joke” API. Beside the lunch pad click the + sign… Enter into the address bar. Click the “Headers” tab and add an entry for Accept with a value of application/json. Then click “Send” and enjoy your joke 🙂

ngrok Installation
Navigate to
Click the download link for “Windows”. (If you are using a 32 bit version of Windows, be sure to change the option.)
Open the zip file and extract it to the ngrok subdirectory under your user folder.

If you do not already have Cisco AnyConnect installed, you can install OpenConnect for an open source VPN client to use to connect to DevNet Sandboxes.

Navigate to the OpenConnect-GUI Releases page.
Download the latest Windows release.
Run the downloaded installer with the following suggestions.
On the “Install Options” page, “Add the openconnect-gui to the system PATH for all users.”
Also on the “Install Options” page, “Create openconnect-gui Desktop Icon.”
To fully verify OpenConnect installation you’ll need a VPN server to connect to. If you don’t have one handy, go on over to the DevNet Sandbox Catalog and reserve one of our possible sandboxes. Once the reservation is ready, you’ll be provided the VPN credentials to connect to.
Open the OpenConnect GUI, and create a “New profile.” Enter the VPN address as the “Gateway” and “Save & Connect”. You’ll then be prompted for your username and password.

You should now have an active VPN connection to your sandbox, and be able to reach the resources contained within your pod.

Step 7: Application Container Engine
DevNet Express Cloud Collaboration for IT Pros participants can skip Docker installation

Docker for Windows 10 leverages the Hyper-V feature of the operating system and requires you enable it before Docker for Windows will install and work.
Open the “Turn Windows features on or off” control panel.
Make sure both “Hyper-V Management Tools” and “Hyper-V Platform” are enabled under “Hyper-V”.
Changes to these settings will require a reboot of the workstation.
NOTE: While the Hyper-V feature is enabled on Windows 10, other hypervisor platforms like VirtualBox and VMware Workstation will NOT work.

Navigate to Install Docker Desktop on Windows.

Click “Download from Docker Hub” link. The new page is refreshed with “Docker Desktop for Windows” details.
Click “Get Docker” link to start download.
Run the downloaded installer taking the defaults.

Please make sure that you will turn ON the virtualization in the BIOS.
If any error occurs during Docker installation, refer to Docker troubleshooting page.

Open a git-bash terminal.
Enter the following command to start a test container based on the “busybox” image.

docker run busybox

The container will start, and then stop showing no output. Verify it worked with the following command.

docker ps -a
# Sample Output
d9a3285ba957 busybox “sh” 20 seconds ago Exited (0) 15 seconds ago quizzical_bartik

First, clone a repository
The Getting Started project is a simple GitHub repository which contains everything you need to build an image and run it as a container.

Install Git if you don’t have it already.

git clone

Now, build the image
A Docker image is a private file system just for your container. It provides all the files and code your container needs.

cd getting-started
docker build -t docker101tutorial .

Run your first container
Start a container based on the image you built in the previous step. Running a container launches your application with private resources, securely isolated from the rest of your machine.

docker run -d -p 80:80 –name docker-tutorial docker101tutorial

Now save and share your image
You must be signed in to Docker Hub to share your image.


The next step will be to access this link –

using your cisco account. If you dont have one already, create a free Cisco account.

Overlay vs Underlay Networks

Overlay vs Underlay Networks tiptechnoloy_0sppo6

Difference Between Overlay And Underlay Network In Tabular Form

Description Underlay Network is physical infrastructure above which overlay network is built. An Overlay Network is a virtual network that is built on top of an underlying Network infrastructure/Network layer (the underlay).
Traffic Flow Transmits packets which traverse over network devices like switches and routers. Transmits packets only along the virtual links between the overlay nodes.
Deployment Time Less scalable and time consuming activity to setup new services and functions. Ability to rapidly and incrementally deploy new functions through edge-centric innovations.
Packet Control Hardware oriented. Software oriented.
Packet Encapsulation And Overhead Packet delivery and reliability occurs at layer-3 and layer-4. Needs to encapsulate packets across source and destination, hence incurs additional overhead.
Multipath Forwarding Less scalable options of multipath forwarding. In fact using multiple paths can have associated overhead and complexity. Support for multi-path forwarding within virtual networks.
Managing Multitenancy NAT or VRF based segregation required which may face challenge in big environments. Ability to manage overlapping IP addresses between multiple tenants.
Scalability Less Scalable due to technology limitation. Designed to provide more scalability than underlay network. E.g VLAN (Underlay Network) provides 4096 VLAN support while VXLAN (Overlay Network) provides up to 16 million identifiers.
Packet Delivery Responsible for delivery of packets. Offloaded from delivery of packets.
Protocols Underlay protocols include Ethernet Switching, VLAN, Routing etc. Overlay network protocols include Virtual Extensible LAN (VXLAN), Network Virtualization using Generic Encapsulation (NVGRE), Stateless Transport Tunneling (STT), Generic Routing Encapsulation (GRE), IP multicast and Network Virtualization overlays 3 (NVO3).


Old protocols = VLANs and MPLS, are now replaced by VXLAN which is more scalable .


Top 10 Web Application Security Risks

Top 10 Web Application Security Risks tiptechnoloy_0sppo6

Top 10 Web Application Security Risks

  1. Injection
  2. Broken Authentication
  3. Sensitive Data Exposure

Network and Data Science BootCamp July-Sep 2020

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The Benefits of Cyber Security and AI

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