30 TOP Angular 4 Interview Questions and Answers pdf download

Here are top 30 Angular 4 Interview questions and their answers are given just below to them. These sample Angular 4 questions are framed by experts. who train for Learn Angular 4 Online to give you an idea of type of questions which may be asked in interview. We have taken full care to give correct answers for all the Angular 4 questions. Do comment your thoughts. Happy Job Hunting!
Top 30 Angular 4 Interview Questions Answers

1. What Are Angular 4?

Ans: 
On 13 December 2016 Angular 4 was announced, skipping 3 to avoid confusion due to the misalignment of the router package’s version which was already distributed as v3.3.0. The final version was released on March 23, 2017. Angular 4 is backward compatible with Angular 2.
Angular version 4.3 is a minor release, meaning that it contains no breaking changes and that it is a drop-in replacement for 4.x.x.

2. Explain The Component Directory Structure Of Angular 4?

Ans: 
Here are the elements which are present in the component directory structure anf modules: –
Module.ts- in this, the angular module is declared. @NgModule decorator is used which initializes the different aspects of angular applications. AppComponent is also declared in it.
Components.ts- it simply defines the components in angular and this is the place where the app-root sector is also defined. A title attribute is also declared in the component.
Component.html- it is the template file of the application which represents the visual parts of our components.

3. What Is The Use Of Interceptors In Angular 4?

Ans: 
The Interceptors is a common used to set default headers for all responses.

4. What Happen When I Import The Same Module Twice In Angular 4?

Ans: 
No problem! We can import the same module twice but Angular does not like modules with circular references.
So do not let Module “X” import Module “Y” which already imports Module “X”.
When four modules all import Module “X”, Angular estimate Module “X” once, the first time face it and does not do again. Actually, the modules help us to organize an application into associative blocks of functionality.

5. How To Set Http Request Header In Angular 4 And Angular 2?

Ans: 
The HTTP Interceptors are used to Set Http Headers Request in Angular 4 using the import from “@angular/common/http”. The HTTP Interceptors are available in Angular 4.x versions.
The HTTP Interceptors are not supported in Angular 2. We are creating the Http Client Injectable class to achieve this. You can see the below examples for set http headers request with and without HTTP interceptors.

6. What Are The Differences Between Angular And Angular Js?

Ans: 
Angular was a ground-up rewrite of AngularJS and has many unique features.
Angular does not have a concept of “scope” or controllers; instead it uses a hierarchy of components as its main architectural concept
Angular has a different expression syntax, focusing on “[ ]” for property binding, and “( )” for event binding
Mobile development – desktop development is much easier when mobile performance issues are handled first
Modularity – much core functionality has moved to modules, producing a lighter, faster core
Modern browsers only – reducing the need for browser compatibility workarounds
Angular recommends the use of Microsoft’s Typescript language, which introduces the following features:
Class-based Object Oriented Programming
Static Typing
Generics
Typescript a superset of ECMAScript 6 (ES6), and is backwards compatible with ECMAScript 5 (i.e.: JavaScript).
Angular also includes the benefits of ES6:
Lambdas
Iterators
For/Of loops
Python-style generators
Reflection
Improved dependency injection– bindings make it possible for dependencies to be named
Dynamic loading
Asynchronous template compilation
Simpler Routing
Replacing controllers and $scope with components and directives – a component is a directive with a template.
Reactive programming support using RxJS.

7. What’s New In Angular 4? And What Are The Improvements In Angular 4?

Ans: 
Angular 4 contains some additional Enhancement and Improvement.
Consider the following enhancements:
Smaller & Faster Apps
View Engine Size Reduce
Animation Package
NgIf and ngFor Improvement
Template
Ng If with Else
Use of AS keyword
Pipes
HTTP Request Simplified
Apps Testing Simplified
Introduce Meta Tags
Added some Forms Validator Attributes
Added Compare Select Options
Enhancement in Router
Added Optional Parameter
Improvement Internationalization

8. Why Angular 4? What’s New In Angular 4?

Ans: 
It Makes work easier compared with angular 2 and other models.
Writing code is lots of cleaner and lesser.
It Improve the execution performance for Data binding and so on.
It has included Animations features.
In Angular 4, no need to apply observable methods because Angular analyses every page’s DOM and it is automatically modifies to page’s DOM.
It is also supported by Visual Studio, IntelliJ, And NET IDES and so on.
Migration is really very soft and cleaner.
And So On…
Angular 2 apps will work using Angular 4 without changing anything. Angular 4 offers lots-of enhancements i.e.
Smaller & Faster Apps
View Engine Size Reduce
Animation Package
NgIf and ngFor Improvement
Overriding Template
NgIf with Else
Use of AS keyword
Pipes
HTTP Request Simplified
Apps Testing Simplified
Introduce Meta Tags
Added some Forms Validator Attributes
Added Compare Select Options
Enhancement in Router
Added Optional Parameter
Improvement Internationalization
Meaningful errors handling methodology
Animations

9. What Do I Have To Do To Trick The Browser Into Doing What I Want?

Ans: 
The impedance mismatch between dynamic applications and static documents is often solved with:
A library – a collection of functions which are useful when writing web apps. Your code is in charge and it calls into the library when it sees fit. E.g., jQuery.
Frameworks – a particular implementation of a web application, where your code fills in the details. The framework is in charge and it calls into your code when it needs something app specific.
E.g., durandal, ember, etc.
AngularJS takes another approach. It attempts to minimize the impedance mismatch between document centric HTML and what an application needs by creating new HTML constructs. AngularJS teaches the browser new syntax through a construct we call directives.
Examples include:
Data binding, as in {{}}.
DOM control structures for repeating, showing and hiding DOM fragments.
Support for forms and form validation.
Attaching new behavior to DOM elements, such as DOM event handling.
Grouping of HTML into reusable components.

10. What Is Angular?

Ans: 
Angular (commonly referred to as “Angular 2+” or “Angular 2“):
Is a TypeScript-based open-source front-end web application platform bed by the Angular Team at Google and by a community of individuals and corporations to address all of the parts of the developer’s workflow while building complex web application. Angular is a complete rewrite from the same team that built AngularJS.
Angular is a framework for building client applications in HTML and either JavaScript or a language like TypeScript that compiles to JavaScript. Angular combines declarative templates, dependency injection, end to end tooling, and integrated best practices to solve development challenges. Angular empowers developers to build applications that live on the web, mobile, or the desktop.

11. What Is The For Root Method?

Ans: 
The for Root is a static method and it’s very easy for developers to configure the modules and the best example is – RouterModule.for Root.
The Router Module also offers a for Child. It’s also a static method and use to configure the routes of lazy-loaded modules. The for Root and for Child are the traditional names for methods that configure services in root.

12. What Is The Difference Between `{'ngfor'}` And `{`ngforof`}` In Angular 2?

Ans: 
Angular 2 – ngFor vs. ngFor:
The [ngFor] is not a type safe.
The [NgForOf] is a type Safe.
The [NgFor] directive instantiates a template once per item from iterate.
The [ngFor] and [ngForOf] are actually the selectors of the [NgForOf] directive and it is not two distinct things.
The [ngFor] will be works like as collections.
The [ngForOf] will be works like as generics.

13. What Classes Should I Add To Module's Declarations?

Ans: 
We can add the declarable classes like components, directives and pipes in the module’s declarations list and we can add only – components, directives and pipes classes in the @NgModule.

14. What Classes Should I Not Add To Module's Declarations?

Ans: 
We do not declare – Module, Service, objects, strings, numbers, functions, entity models, configurations, business logic, and helper classes in the module’s declarations.

15. What Is Angular Js?

Ans: 
AngularJS is a structural framework for dynamic web apps. It lets you use HTML as your template language and lets you extend HTML syntax to express your application’s components clearly and succinctly. AngularJS data binding and dependency injection eliminate much of the code you would otherwise have to write. And it all happens within the browser, making it an ideal partner with any server technology.
AngularJS is what HTML would have been, had it been designed for applications. HTML is a great declarative language for static documents. It does not contain much in the way of creating applications, and as a result building web applications is an exercise in.

16. How To Get And Log An Error In Angular 4?

Ans: 
Two types of error:
If the backend returned an unsuccessful response like – 404, 500 and so on.
If something goes wrong in the client side like -network error etc.
In the both cases – We are using Http Error Response and return the useful information on what went wrong in this call!

17. How Are Jwts Used To Authenticate Angular 4 Applications?

Ans: 
In Annular, the following Steps are used to building authentication and authorization for RESTful APIs and applications. It might help you –
The users send their credentials to the server which is verified by the database credentials. If everything is verified successfully, the JWT is sent back to them.
The JWT is saved in the user’s browser in local storage or in a cookie and so on.
The presence of a JWT saved in the browser is used as an indicator that a user is currently logged in.
The expiry time of JWT is continually checked to maintain an authenticated state in the Angular applications.
The client side routes are protected and access by authenticated users only.
When user sends the XHR requests for APIs, the JWT gets sent an Authorization header using your cookies or Bearer.
When XHR requests coming on the server, before send back the responses it’s validated first with configured app’s secret keys. If everything is looking good then returns successfully responses other send the back to the bad request.
There are several open source libraries are available for angular which are helps with JWTs and has the ability to Decode the JWT, Authorization header to XHR requests and so on.

18. What Is Json Web Token?

Ans: 
JSON Web Token (JWT) is an open standard which used for securely transmitting information between parties as a JSON object.
The JWTs can be signed with –
HMAC algorithm
RSA algorithm

19. When Should You Use Json Web Tokens?

Ans: 
There are some scenarios where we can used JSON Web Tokens –
Authentication
Information Exchange

20. What Is The Json Web Token Structure?

Ans: 
The JSON Web Tokens consist of three parts separated by dots (.), which are:
Header
Payload
Signature

21. Explain Component Decorators In Angular 4?

Ans: 
A decorator is the core concept when developing an angular framework with version 2 and above. It may become a core language feature for JavaScript soon. In angular 4, decorators are used extensively and are also used to compile a code.
There are 4 different types of decorators:
Class decorators
Property decorators
Method decorators
Parameter decorators
A decorator is a function that is invoked with a prefix “@” symbol and is immediately followed by a class, parameter, method, or property. A decorator returns the same thing which was given as an input but in an augmented form.

22. Write The Cli Command To Generate A Component In Angular 4?

Ans: 
Components are just simple classes which are declared as components with the help of component decorators.
It becomes easy to create an application which already works, with the help of angular CLI commands. “Ng generate” is used to generate components, routes, services, and pipes. Simple test shells are also created with the help of this CLI command. For generating a component in angular4 with the help of CLI command.
you need to follow the following syntax-
ng generate component component name;
It generates the component and adds the component to module declarations.

23. What Are The Features Of Angular 4.3?

Ans:
Features in Angular version 4.3 are:
Introducing Http Client, a smaller, easier to use, and more powerful library for making HTTP Requests.
New router life cycle events for Guards and Resolvers. Four new events: GuardsCheckStart, GuardsCheckEnd, ResolveStart, ResolveEnd join the existing set of life cycle event such as NavigationStart.
Conditionally disable.

24. Explain Ngfor Directive With An Example?

Ans: 
The ngFor directive instantiates a template for every element of the given iterator. The different local variables of the ngFor directive can be used in iterations. The ngFor directive can even be used with the HTML elements. It also performs various changes in DOM. Several exported values can be aliased to local variables with the help of ngFor directive. It allows us to build data presentation lists and tables in our HTML templates.
Here’s an example of ngFor directive with the help of HTML:
<tr *ngFor=”hero of heroes”>
<td>({hero.name})</td></tr>

25. Explain Property Binding Or One Way Binding In Angular Js?

Ans: 
Basically property binding means passing data from the component class and setting the value of a given element in the view. It is a one way binding in which the data is passed from component to the class. It allows us to control the element property values from component to class. Property binding in angular can take place by three ways:
Interpolation can be used to define a value, as long as the value being defined is a string.
Wrapping brackets around the element property and binding it to the component property is the most common type of property binding.
The third way is by adding “bind” before the element property.

26. Explain Ngif Directive With An Example?

Ans: 
The ngIf is a built-in template directive which is used to add or remove some parts of DOM. This addition or removal depends on the expression being true or false.
If the expression is evaluated to false, then the ngIf directive removes the HTML element. If the expression is evaluated to be true, then the element gets added to the DOM.
Syntax- *ngIf=”<condition>”
Example- <ul *ngFor=”let person of people”
*ngIf=”person.age < 30”>
<li>{{person.name}}</li></ul>

27. Write The Difference Between Directive And Component In Angular Js?

Ans: 
In angular js, there are differences between the meta-data annotations. Some of the differences are:
A directive is used to add behaviour to an existing element. Whereas, a component is used to create a component with attached behaviour.
“@directive” is used to create a directive. Whereas, “@component” is used to create a component.
A directive is used to attach different behaviours to an existing DOM element. Whereas, with the help of component, we can break our application into smaller components.
A directive is used to create reusable behaviour. Whereas, a component is used to create reusable components.
A directive does not require a view. Whereas, a component needs a view via @view.

28. What Do You Understand By Isolated Unit Tests?

Ans: 
As the name implies, unit test is all about testing individual units of code. In order to answer some questions, isolating the unit of code under test is really important. When we do this, we are not forced into creating related pieces such as DOM elements for sorting. With the help of isolated unit tests, it becomes easier to implement everything. To simulate the requests, dependency injections are also provided. The individual sort function can be tested in isolation. And not only the sort function, any function can be tested in isolation.

29. What Is A Routing In Angular Js?

Ans: 
NgRoute module is used when you want to navigate through different pages of your application but you also want your application to be a single page application. This ngRoute module navigates through different pages of your application without reloading the entire application. The angular js route module should be included to make your application ready for routing. The ngRoute is added as a dependency in the application. The routing engine captures the specific url requested by the user and renders the view based on the defined routing rules.

30. What Do You Understand By Services With Reference To Angular Js?

Ans:
Services in angular js are used to organize and share code across your application. These are the suitable objects which are wired together with the help of dependency injection. The angular js services are lazily instantiated. The service is only instantiated by angular js only when the application component depends on it. In angular js, new services can be made or can even be used in other built-in services. Over 30 built-in services are present in angular js.

20 TOP RPA Blue Prism Interview Questions & Answers pdf

Here are top 20 BLUE PRISM Interview questions and their answers are given just below to them. These sample RPA BLUE PRISM questions are framed by experts. who train for Learn BLUE PRISM Online to give you an idea of type of questions which may be asked in interview. We have taken full care to give correct answers for all the questions. Do comment your thoughts. Happy Job Hunting!

1.    What is Robotic Automation?
Robotic automation is a type of automation where a machine or computer mimics a human’s action in completing rules based tasks.

2.    What is Blue Prism’s Robotic Automation?
Robotic Automation implies process Automation’s where computer software drives existing enterprise application software in the same way that a user does. Automation is a gadget or stage that operates other application software through the existing application UI.

3.    Is Robotic Automation like screen scraping or macros?
No, managerial Robotic Automation is a generation on from old technologies like screen scratching or macros.
The major differences are:
Robots are universal application orchestrators – any application that can be used by a man can be used by a present day robot, whether mainframe, bespoke application, legacy, web service enabled or even a close 3rd party API hosted service.
Robots assemble procedural knowledge which after some time joins with a shared library that can re-used by some other robot or device.
Applications are “read” by the robot, either through submitted APIs where they exist, through the OS before application appear, or through the screen with respect to the native application. In this last case the modern robot “reads” an application screen in context and in the same way a user does. As part of the robot training it is shown how to read the application’s display much like a user is shown.

4.    Is Blue Prism an RPA Tool?
Yes, Blue Prism is an RPA Tool.
blue prism developer interview questions

5.    What systems can Blue Prism robotically integrate?
Blue Prism has incorporated several years of experience of integration and various technologies into its software. The technologies used are secure, reliable and robust. Instead of creating new adaptors for each unique application we have developed technology adaptors for all the technologies employed at the presentation layer, Windows, Web, Java, Green Screen/Mainframe and even Citrix.
This consolidated with a broad assortment of dedicated tools that have been developed means that we are confident in being able to link any system with the click of a button. This proven application orchestration ability ensures that new processes can be quickly designed, built and tested without any impact on existing systems.

6.    What hardware infrastructure do I need to run Blue Prism’s Robotic Automation Platform?
Blue Prism has been uniquely designed for flexibility and to meet the most robust IT standards for IT operational integrity, security and sup portability. The software can be deployed either as a front office or back office process, running quite happily on a standard desktop in the front office or on any scale of systems for back office processing.

7.    What is process Studio?
A Blue Prism Process is created as a diagram that looks like a business flow diagram. Processes are created in a zone of Blue Prism named Process Studio which looks similar to other process modeling applications) and uses standard flow diagram symbols and notation.

8.    Is Blue Prism’s Robotic Automation Platform secure and auditable?

Security and auditability are consolidated into the Blue Prism robotic automation platform at various levels. The runtime environment is totally separate to the process editing environment.
Approvals to design, create, edit and run processes and business objects are specific to each authorized user.
A full audit trail of changes to any process is kept, and comparisons of the before and after effect of changes are rovided.
The log created at run-time for each process provides a detailed, time-stamped history of every action and decision taken within an automated process.
Our clients tend to find that running a process with Blue Prism gives them a lot more control than a manual process, and from a compliance point of view assures that processes are run consistently, in line with the process definition.

9.    How do I get started on delivering processes using Blue Prism?
Blue Prism acclaims a phased approach to getting started as the Operational Agility framework is very scalable. It is typical to target the configuration of between 1 and 10 processes initially with a rolling program of processes being introduced once the outline is established.

10.    What support do I need from Blue Prism Professional Services?

It genuinely depends on the capacities you already have in house and the way you wish to work. Blue Prism can give a full extent of services from basic training, reinforce and mentoring with a view to quickly getting your team independently delivering ongoing automations, right through to a full turnkey package where we will take responsibility for delivering business benefit within agreed service levels.

11.    Why Blue Prism?
Reasons:
  • Supports both internal and external Encryption/Decryption Keys
  • Automation process can be designed within IT Governance
  • High level Robustness because of .NET customized code within the process automation
  • Provides Audit Logs enabling
12.    How much does robotic automation cost?
A “fully loaded” office robot is around a 1/3rd the cost of universally sourced agents. The flexibility and ease of disposition means that this comparison is easy to maintain and judge the nest method to a given tasks.

13.    What is the difference between thin client and thick client?
Thin client: It is any application that we cannot get the quality properties while spying using any RPA tools. For e.g.  Citrix or any virtual environment.
Thick client: It is any application that we get pretty handful of attribute properties using RPA tools e.g. calculator, Internet explorer

14.    Does blue prism require coding?
Blue Prism’s digital workforce is fabricated, managed and asserted by the user or customer, spanning operations and technology, sticking to an enterprise-wide robotic operating model. It is code-free and can computerize any software.
The digital workforce can be applied to automate processes in any department where managerial or administrative work is performed over an organization.

15.    What are the differences between Blue Prism and UiPath?
UiPath and Blue Prism both the tools have their own software and they are very good. UI and BP both have graphic process designers for developing the solutions.
Differences:
In terms of programming languages
Blue Prism Uses C# for coding
UiPath uses VB for coding
In terms of Control Room/Dashboard
UiPath control room – The Orchestrator – is web based; you can access it from the browser or mobile.
BP has client based servers, accessible only through their apps.
In terms of cost and uses
UiPath
  • Lower cost of development
  • Easier to learn and operate
  • You can learn by your self
  • Study materials are easily available on internet
 Blue Prism
  • Good for mass scale deployment of large number of rob.

Latest ASA Firewall Multiple choice Questions and Answers pdf

51. Explain Security Context?
We can partition a Single ASA into multiple virtual devices, known as Security Contexts. Each Context acts as an independent device, with its own security policy, interfaces, and administrators. Multiple contexts are similar to having multiple standalone devices.

52. What features are supported in multiple context mode?
Routing tables, Firewall features, IPS, and Management.

53. What features are not supported in multiple context mode?
VPN and Dynamic Routing Protocols.

54. Explain System area?
When we boot up in multiple mode from the CLI, we are taken into the system area. The system area is used to create and manage the contexts, configure the physical properties of the interfaces, create VLANs for trunking, create resource classes to restrict the context system resource usage.

55. What is the admin context?
When the appliance boots up, one context is automatically created called Admin Context which defaults to being the administrative context. Any context can be made administrative context. One of the contexts on our appliance must be the administrative context. An “*” beside a context name indicates that the context is the administrative context.

56. How ASA classifies packets?
The packet that enters is to be processed by which context is classified by ASA as follows:-
1.Unique Interfaces - If only one context is associated with the ingress interface, the ASA classifies the packet into that context.
2.Unique MAC Addresses - If multiple contexts share an interface, then the interface MAC address is used as classifier. ASA lets us assign a different MAC address in each context to the same shared interface. By default, shared interfaces do not have unique MAC addresses. We can set the MAC addresses manually or we can automatically generate MAC addresses by # mac-address auto command.
3.NAT Configuration - If we do not use unique MAC addresses, then the mapped addresses in our NAT configuration are used to classify packets.

57. What is the command to switch to multiple context Mode?
# mode multiple
After entering this command the appliance will reboot itself and our current configuration is automatically backed up to flash in case we want to switch back to single mode. The file is called “old_running.cfg.”

58. What is the command to switch back to single mode?
# mode single

59. What are different types of NAT in ASA?
Static NAT - A consistent mapping between a real and mapped IP address. It allows Bidirectional traffic initiation.
Dynamic NAT - A group of real IP addresses are mapped to a (usually smaller) group of mapped IP addresses on a first come first served basis. It allows only Unidirectional traffic initiation.
Dynamic Port Address Translation (PAT) - A group of real IP addresses are mapped to a single IP address using a unique source port of that IP address.
Identity NAT - A real address is statically translated to itself, essentially bypassing NAT.

60. What is Policy NAT?
Policy NAT allows you to NAT by specifying both the source and destination addresses in an extended access list. We can also optionally specify the source and destination ports. Regular NAT can only consider the source addresses, not the destination address.
In Static NAT it is called as Static Policy NAT.
In Dynamic NAT it is called as Dynamic Policy NAT.

61. Give the order of preference between different types of NAT?
1.Nat exemption.
2.Existing translation in Xlate.
3.Static NAT
- Static Identity NAT
- Static Policy NAT
- Static NAT
- Static PAT
4.Dynamic NAT
- NAT Zero
- Dynamic Policy NAT
- Dynamic NAT
- Dynamic PAT

62. What is the difference between Auto NAT & Manual NAT?
Auto NAT (Network Object NAT) - It only considers the source address while performing NAT. So, Auto NAT is only used for Static or Dynamic NAT. Auto NAT is configured within an object.
Manual NAT (Twice NAT) - Manual NAT considers either only the source address or the source and destination address while performing NAT. It can be used for almost all types of NAT like NAT exempt, policy NAT etc.
Unlike Auto NAT that is configured within an object, Manual NAT is configured directly from the global configuration mode.

63. Give NAT Order in terms of Auto NAT & Manual NAT?
NAT is ordered in 3 sections.
Section 1 – Manual NAT
Section 2 – Auto NAT
Section 3 – Manual Nat After-Auto

64. What are the command to see NAT Translations?
# sh xlate
# sh nat

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41. What are the Failover Requirements between two devices?
Hardware Requirements - The two units in a failover configuration must be the same model, should have same number and types of interfaces.
Software Requirements - The two units in a failover configuration must be in the same operating modes (routed or transparent single or multiple context). They must have the same software version.

42. Explain Active/Standby Failover?
In Active/Standby Failover, one unit is the active unit which passes traffic. The standby unit does not actively pass traffic. When Failover occurs, the active unit fails over to the standby unit, which then becomes active. We can use Active/Standby Failover for ASAs in both single or multiple context mode.

43. Explain Active/Active Failover?
It is only available for ASAs in multiple context mode. In an Active/Active Failover configuration, both ASAs can pass network traffic. In Active/Active Failover, we divide the security contexts on the ASA into Failover Groups. A Failover Group is simply a logical group of one or more security contexts. Each group is assigned to be active on a specific ASA in the failover pair. When Failover occurs, it occurs at the Failover group level.

44. What is the command to enable Failover?
# Failover

45. What is the command to see Failover?
# sh failover

46. Explain Unit Health Monitoring in Failover? How Failover occurs?
The ASA unit determines the health of the other unit by monitoring the failover link. When a unit does not receive three consecutive hello messages on the failover link, it sends hello messages on each interface, including the failover interface, to find whether or not the other unit is responsive.
Based upon the response from the other unit it takes following actions:-
1.If the ASA receives a response on the failover interface, then it does not failover.
2.If the ASA does not receive a response on the failover link, but it does receive a response on another interface, then the unit does not failover. The failover link is marked as failed.
3.If the ASA does not receive a response on any interface, then the standby unit switches to active mode and classifies the other unit as failed.

47. How active unit is determined in Active/Standby Failover?
1.If a unit boots and detects another unit already running as active, it becomes the standby unit.
2.If a unit boots and does not detect active unit, it becomes the active unit.
3.If both units boot simultaneously, then the primary unit becomes the active unit, and the secondary
unit becomes the standby unit.

48. Name some commands replicated to standby unit?
All configuration commands except for mode, firewall, and failover lan unit are replicated to standby unit.
# copy running-config startup-config
# write memory

49. Name some commands that are not replicated to standby unit?
All forms of the copy command except for # copy running-config startup-config
all forms of the write command except for # write memory

50. Explain Active/Standby Failover & Active/Active Failover in terms of preemption?
In Active/Standby Failover there is no preemption.
In Active/Active Failover preemption is optional.

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31. What are the differences between switch and ASA (in Transparent mode) ?
ASA does not floods unknown unicast frames that are not found in mac address table.
ASA does not participate in STP.
Switch process traffic at layer 1 & layer 2 while ASA can process traffic from layer 1 to layer 7.

32. What are the features that are not supported in Transparent mode?
1.Dynamic Routing.
2.Multicasting.
3.QOS.
4.VPNs like IPSec and WebVPN cannot be terminated.
5.ASA cannot act as DHCP relay agent.

33. Explain Ether-Type ACL?
In Transparent mode, unlike TCP/IP traffic for which security levels are used to permit or deny traffic all non-IP traffic is denied by default. We create Ether-Type ACL to allow NON-IP traffic. We can control traffic like BPDU, IPX etc with Ether-Type ACL.

34. What is the command to convert ASA into Transparent mode?
# firewall transparent

35. What is the command to see mode (routed or transparent)?
# sh firewall

36. Explain Failover?
Failover is a cisco proprietary feature. It is used to provide redundancy. It requires two identical ASAs to be connected to each other through a dedicated failover link. Health of active interfaces and units are monitored to determine if failover has occurred or not.

37. What are type of Failover?
1.Active/Standby Failover.
2.Active/Active Failover.

38. What information is exchanged between ASAs over a Failover link?
1.State - Active or standby.
2.Hello Messages.
3.Network Link Status.
4.Mac Addresses.
5.Configuration Replication and Synchronization.

39. What is the difference between Stateful failover and Stateless failover?
Stateless Failover - When failover occurs all active connections are dropped. Clients need to re-establish connections when the new active unit takes over.
Stateful Failover - The active unit continually passes per-connection state information to the standby unit. After a failover occurs, the same connection information is available at the new active unit. Clients are not required to reconnect to keep the same communication session.

40. What Information Active unit passes to the standby unit in Stateful Failover?
NAT translation table, TCP connection states, The ARP table, The Layer 2 bridge table (when running in transparent firewall mode), ICMP connection state etc.

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21. What is the difference in ACL on ASA than on Router?
In router, if we delete one access-control entry whole ACL will be deleted. In ASA, if we will delete one access-control entry whole ACL will not be deleted.

22. Name some concepts that cannot be configured on ASA?
Line VTY cannot be configured on ASA.
Wildcard mask concept is not present in ASA.
Loopback cannot be configured on ASA.

23. What is the command to capture packets in ASA?
To capture packet from inside interface:- # capture abc interfacer inside
To see it:- # sh capture abc

24. What is the command to enable HTTP on ASA?
# http server enable

25. How to give static route on ASA?
# route outside <Destination IP> <Subnet Mask> < Next Hop>

26. How to give default route on ASA?
# route outside 0 0 < Next Hop>

27. What are the different types of ACL in Firewall?
1.Standard ACL
2.Extended ACL
3.Ethertype ACL (Transparent Firewall)
4.Webtype ACL (SSL VPN)

28. What is Tranparent Firewall?
In Transparent Mode, ASA acts as a Layer 2 device like a bridge or switch and forwards Ethernet frames based on destination MAC-address.

29. What is the need of Transparent Firewall?
If we want to deploy a new firewall into an existing network it can be a complicated process due to various issues like IP address reconfiguration, network topology changes, current firewall etc. We can easily insert a transparent firewall in an existing segment and control traffic between two sides without having to readdress or reconfigure the devices.

30. What are the similarities between switch and ASA (in Transparent mode) ?
Both learns which mac addresses are associated with which interface and store them in local mac address table.

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11. Does ASA inspects ICMP?
No, ASA does not inspect ICMP by default.

12. Explain DMZ (Demilitarized Zone) Server?
If we need some network resources such as a Web server or FTP server to be available to outside users we place these resources on a separate network behind the firewall called a demilitarized zone (DMZ). The firewall allows limited access to the DMZ, but because the DMZ only includes the public servers, an attack there only affects the servers and does not affect the inside network.

13. How does a firewall process a packet?
When a packet is received on the ingress interface, the ASA checks if it matches an existing entry in the connection table. If it does, protocol inspection is carried out on that packet.
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If it does not match an existing connection and the packet is either a TCP-SYN packet or UDP packet, the packet is subjected to ACL checks.The reason it needs to be a TCP-SYN packet is because a SYN packet is the first packet in the TCP 3-way handshake. Any other TCP packet that isn’t part of an existing connection is likely an attack.
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If the packet is allowed by ACLs and is also verified by translation rules, the packet goes through protocol inspection.
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Then, the IP header is translated if NAT is used and if the NAT rule specifies an egress interface, the ASA will virtually forward the packet to this egress interface and then perform a route lookup.
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If a route is found that specifies the egress interface, then the Layer-2 header of the packet is re-written and the packet is forwarded out the egress interface.

14. What are the values for timeout of TCP session, UDP session, ICMP session?
TCP session - 60 minutes
UDP session - 2 minutes
ICMP session - 2 seconds

15. Explain TCP Flags?
While troubleshooting TCP connections through the ASA, the connection flags shown for each TCP connection provide information about the state of TCP connections to the ASA.

16. What is the command to see timeout timers?
# sh run timeout

17. What is the Difference between ports in ASA 8.4 and ASA 8.2?
In ASA 8.4 all ports are Gig ports and in ASA 8.2 all are Ethernet ports.

18. What is the command to check connection table?
# sh conn

19. How ASA works in reference to Traceroute?
ASA does not decrement the TTL value in traceroute because it does not want to give its information to others for security purpose. It forwards it without decrementing the TTL Value.

20. What if we apply ACL as global in ASA?
It will be applied on all interfaces towards inbound. Global option is only in ASA 8.4 not in ASA 8.2

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