An Overview on Cisco Viptela SD-WAN

Cisco SDWAN Viptela solution comprises of the following components:
vManage Network Management System (NMS)

Image source https://sdwan-docs.cisco.com

The vManage NMS is a centralized network management system that lets you configure and manage the entire overlay network from a simple graphical dashboard. vManage provides a single pane of glass for configuration and monitoring the SDWAN network. If vManage is offline, traffic forwarding continues on the SDWAN fabric due to separation of control and data plane in the SDWAN fabric.
vSmart Controller
The vSmart controller is the centralized brain of the SDWAN solution, controlling the flow of data traffic throughout the network. The vSmart controller works with the vBond orchestrator to authenticate SDWAN devices as they join the network and to orchestrate connectivity among the SDWAN routers.The vSmart controllers are the central orchestrators of the control plane. They have permanent communication channels with all the SDWAN devices in the network. Over the DTLS connections between the vSmart controllers and vBond orchestrators and between vSmart controllers, the devices regularly exchange their views of the network, to ensure that their route tables remain synchronized.If the vSmart controllers go offline, the SDWAN routers will continue forwarding traffic based on last known configuration state up to a configurable graceful period timer expiry.

Udacity has special offers worldwide to help anyone learn important, higher-paying job skills during this challenging time. Click here to get your offer and start learning now!

vBond Orchestrator
The vBond orchestrator automatically orchestrates connectivity between SDWAN routers and vSmart controllers. If any SDWAN router or vSmart controller is behind a NAT, the vBond orchestrator also serves as an initial NAT-traversal orchestrator.
The vBond orchestrator automatically coordinates the initial bring-up of vSmart controllers and vEdge routers, and it facilities connectivity between vSmart controllers and vEdge routers. During the bringup processes, the vBond orchestrator authenticates and validates the devices wishing to join the overlay network. This automatic orchestration process prevents tedious and error-prone manual bringup.
vBond is required when:
• a new vEdge router (SDWAN router) joins the network
• A vEdge loses WAN connectivity completely and then regains WAN connectivity
• A vEdge reboots
If vBond is absent in any of the 3 cases above, the vEdge will not be able to join the network.
High availability for vBond is provided by FQDN where a single FQDN is mapped to several IP addresses. The SDWAN router will attempt to reach the IP addresses mapped to the FQDN in the order by which the IP addresses are specified.

ZTP Server
The ZTP server is the 1st point of contact for any new SDWAN router being provisioned into the network. It provides the SDWAN router with the FQDN of the vBond and also helps to provision the enterprise root CA chain into a new SDWAN router that is attempting to join the network.
When setting up the ZTP server, it has to be configured with a list of valid SDWAN router serial numbers, as well as the associated organization names and path to the Enterprise root CA chain (which is uploaded into the ZTP server).
By default, new SDWAN routers are configured with a factory default configuration to look for ZTP server at ztp.viptela.com which is a Cloud based ZTP offering from Cisco. When the SDWAN router initially boots up with the factory default configuration, it attempts to obtain IP/mask on its WAN interface and also DNS server IP via DHCP. In the absence of DHCP, an alternate method of auto-IP is used, where the SDWAN router looks into the physical media between its WAN interface and the upstream provider router and it configures itself with an IP/mask. When autoIP is used, the default DNS settings will be that of Google DNS.
High availability for ZTP is provided by FQDN where a single FQDN is mapped to several IP addresses. The SDWAN router will attempt to reach the IP addresses mapped to the FQDN in the order by which the IP addresses are specified.

SDWAN Routers

The SDWAN routers sit at the perimeter of a site (such as remote offices, branches, campuses, data centers) and provide connectivity among the sites.They are either hardware devices or software that runs as a virtual machine. SDWAN routers handle the transmission of data traffic.

RUST error: linker `link.exe` not found

While compiling Rust program in a windows environment, you may encounter the error : linker `link.exe` not found. This is because of the absence of the C++ build tools in your machine. For compiling Rust programs successfully, one of the prerequisites is the installation of the Build Tools for Visual Studio 2019. Download the Visual Studio 2019 Build tools from the Microsoft website. After the download, while installing the Build tools, make sure that you install the required components (highlighted in Yellow) This will download around 1.2GB of required files. Once everything is successfully installed, reboot and re-run your rust program and it will compile successfully. Read More on RUST Hello World Rust Program : Code explained RUST Cargo Package Manager Explained Data Representation in Rust.

Download Microsoft Office 2019 offline installer.

When you do malware analysis of documents or office files, it is important to have Microsoft Office installed in your Lab machine. I am using flare VM and it doesn't comes with MS Office. Since Microsoft is promoting Microsoft 365 over the offline version, finding the offline installer is not that easy. Here is the list of genuine Microsoft links to download the office .img files. Download Microsoft Office 2019 Professional Plus : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-US/ProPlus2019Retail.img Download Microsoft Office 2019 Professional : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-US/Professional2019Retail.img Download Microsoft Office 2019 Home and Business : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-US/HomeBusiness2019Retail.img Download Microsoft Office 2019 Home and Student : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-U

Cisco ASA: Disable SSLv3 and configure TLSv1.2.

For configuring TLS v1.2, the ASA should run software version 9.3(2) or later. In earlier versions of ASA, TLS 1.2 is not supported.If you are running the old version, it's time to upgrade. But before that i will show you the config prior to the change. I am running ASA version 9.6.1 Now ,set the server-version to tlsv1.2, though ASA supports version tlsv1.1, its always better to configure the connection to more secure. Server here in the sense, the ASA will be act as the server and the client will connect to the ASA. #ssl server-version tlsv1.2 set the client-version to tlsv1.2, if required. #ssl client-version tlsv1.2 ssl cipher command in ASA offers 5 predefined security levels and an additional custom level. #ssl cipher tlsv1.2 high we can see the setting of each cipher levels using #show ssl cipher command. Now set the DH group to 24, which is the strongest offered as of now in the ASA. #ssl dh-group group24 An

How to Install Netmiko on Windows?

Netmiko, developed by kirk Byers is an open source python library based on Paramiko which simplifies SSH management to network devices and is primarily used for network automation tasks. Installing Netmiko in linux is a matter o f one single command but if you need to use Netmiko in your Windows PC, follow this process. 1) Install the latest version of Python. 2) Install Anaconda, which is an opensource distribution platform that you can install in Windows and other OS's (https://www.anaconda.com/download/) 3) From the Anaconda Shell, run “ conda install paramiko ”. 4) From the Anaconda Shell, run “ pip install scp ”. 5) Now Install the Git for Windows. (https://www.git-scm.com/downloads) . Git is required for downloading and cloning all the Netmiko library files from Github. 6) From Git Bash window, Clone Netmiko using the following command git clone https://github.com/ktbyers/netmiko&#8221 7) Once the installation is completed, ch

PrintNightmare (CVE-2021-1675) PoC exploit Walkthrough

I am not an exploit developer but was interested to see how this vulnerability can be exploited. So i tried to replicate the infamous PrintNightmare vulnerability using the following PoCs ( https://github.com/cube0x0/CVE-2021-1675 ) and ( https://github.com/rapid7/metasploit-framework/pull/15385 ) However i had trouble with the new metasploit module (auxiliary/admin/dcerpc/cve_2021_1675_printnightmare) and i couldn't able to exploit the machine successfully. So i tried the second PoC from cube0x0. This one has done the magic. I just followed the guidelines with couple of tweaks. First of all, i installed the impacket (cube0x0 version) which will install the required modules and files. After that i set up a samba share with an anonymous login. This is required for hosting the dll file. I edited the smb.conf with the following settings. [global] map to guest = Bad User server role = standalone server usershare allow guests = yes idmap config * : backend = tdb s

Unable to locate package linux-headers / E: Unable to locate package linux-headers-5.10.0-kali5-amd64

While compiling programs, you may encounter this particular error. E: Unable to locate package linux-headers-5.10.0-kali5-amd64 I encountered this while compiling a C code. To fix this, i first updated my Kali machine (v2020.2a). sudo apt update -y && apt upgrade -y && apt dist-upgrade Rebooted. Then installed the headers. sudo apt install linux-headers-$(uname -r)

Google Cloud : Basic Cloud Shell commands

Google Cloud resources can be managed in multiple ways. It can be done using Cloud Console, SDK or by using Cloud Shell. A few basic Google Cloud shell commands are listed below. 1) List the active account name gcloud auth list 2) List the project ID gcloud config list project 3) Create a new instance using Gcloud shell gcloud compute instances create [INSTANCE_NAME] --machine-type n1-standard-2 --zone [ZONE_NAME] Use gcloud compute machine-types list to view a list of machine types available in particular zone. If the additional parameters, such as a zone is not specified, Google Cloud will use the information from your default project. To view the default project information, use gcloud compute project-info describe 4) SSH in to the machine gcloud compute ssh [INSTANCE_NAME] --zone [YOUR_ZONE] 5) RDP a windows server gcloud compute instances get-serial-port-output [INSTANCE_NAME] --zone [ZONE_NAME] 6) Command to check whether the server is ready f

Difference between Azure management groups, Subscriptions and Resource groups

image courtesy : https://docs.microsoft.com Azure management groups help you manage your Azure subscriptions by grouping them together. If your organization has many subscriptions, you might need a way to efficiently manage access, policies, and compliance for those subscriptions. Azure management groups provide a level of scope above subscriptions. Azure subscriptions help you organize access to Azure resources and determine how resource usage is reported, billed, and paid for. Each subscription can have a different billing and payment setup, so you can have different subscriptions and plans by office, department, project, and so on. Resource groups are containers that hold related resources for an Azure solution. A resource group includes those resources that you want to manage as a group. You decide which resources belong in a resource group based on what makes the most sense for your organization. reference : https://docs.microsoft.com

What is a Gratuitous ARP? How is it used in Network attacks?

Many of us encountered the word "Gratuitous" while exploring the network topic on ARP, The Address Resolution Protocol. Before explaining Gratuitous ARP, here is a quick review on how ARP works. ARP provides IP communication within a Layer 2 broadcast domain by mapping an IP address to a MAC address.For example, Host B wants to send information to Host A but does not have the MAC address of Host A in its ARP cache. Host B shoots a broadcast message for all hosts within the broadcast domain to obtain the MAC address associated with the IP address of Host A. All hosts within the same broadcast domain receive the ARP request, and Host A responds with its MAC address. We can see the ARP entries on our computers by entering the command arp -a . So, back to the topic on what is a Gratuitous reply, here is a better explanation. Gratuitous arp is when a device will send an ARP packet that is not a response to a request. Ideally a gratuitous ARP request is an ARP request packe

Recovery Procedure: Alcatel-Lucent Omni-Switch not booting AOS: Going to Mini-boot prompt.

Problem: Switch not booting AOS; Going to Mini-boot prompt. Model: Alcatel-Lucent OS6850 [Note:The same procedure might be applicable for different models of Omni-Switches, However, for this illustration, i have used OS-6850 ] Reason: This problem may occurs due to corrupt AOS image files or misconfigured boot parameters. Hence switch cannot boot the images properly and will go to Mini-boot prompt. Work Around: [Note: This zmodem procedure consumes a lot to time to finish the process.] 1.) Power off your OS6850 2.) When you switched it back on, stop it before the Miniboot (there is some counter counting down from 4). Press Enter to break. 3.) You will have the following prompt " => " 4.) Enter " setenv baudrate 115200 ”. Increasing baudrate helps to increase the data transfer speed using zmodem. 5.) Enter " saveenv " 6.) Enter " boot " 7.) The switch should run now in baud rate 115200 (so you have to change your clients ter