IIS Interview Questions and Answers [ TOP & MOST ASKED ]

IIS Interview Questions and Answers [ TOP & MOST ASKED ]

Last updated on 10th Nov 2021, Blog, Interview Questions

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Parneet Singh Sachdev (Software Architect-DataStage )

Parneet Singh Sachdev has an in-depth understanding of DataStage, Hadoop, Microsoft Power BI, MicroStrategy, OBIEE, and Cognos. Her interview questions assist in sharing information and helpfull for job seekers.

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    IIS administration is a Microsoft internet information service provides graphical user interface to for managing websites and the associated users. It helps in visual means of creating, configuring, and publishing sites on the web. It guides you how to set up, administer, and secure IIS web server for your organisations. So, you have a greater scope in this field to work as senior administrator, iis administrator, senior application administrator, share point administrator, IT services administrator etc.

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    1) What are the functionalities of ISAPI filters in IIS?


      Some of the functionalities of ISAPI filters include modifying and enhancing the functionality of IIS, filtering the requests to find the one, which is to be processed, and authentication and encryption of the input or output data.

    2)Which are the functions that a protocol listener serves in IIS?


      A protocol typically serves the below three functions:

      • Receiving protocol-specific requests from the client
      • Sending the requests to the client for processing
      • Sending the responses back to requestors

    3) HTTP.SYS is the subsection of which mode?


      HTTP.SYS is the subsection of the Kernel Mode.

    4) What is the functionality of HTTP.SYS?


      HTTP.SYS, which is a protocol listener, receives the client requests, sends them to IIS for processing, and finally returns the responses to the client.

    5) Which are the subsections of User mode?


      The subsections of User mode are Web Admin Service, Virtual Directory, and Application Pool.

    6) What is an Application Host. config in IIS?


      It is the root file of the configuration system, which consists of the following:

      • Applications
      • Virtual directories and application pools
      • Definitions of all sites
      • Global defaults for the webserver settings

    7) What happens if the kernel-mode cache is turned off?


      The impact may not be noticeable if the load is 100 requests per second. However, if it is around 1000 requests per second, the kernel caching will certainly be missed. Ultimately, it all depends on the server load.

    8) What are the advantages of Componentization?


      The advantages of Componentization include:

      • Reduction on the amount of memory the server uses
      • Performance improvement
      • Increased server security with the removal of all unused server features

    9) How do you ensure content security in IIS?


      We can ensure content security by using ACL (Access Control List). It provides allowing or denying permissions to the required identities.

    10) What does a typically shared hosting environment consist of in IIS?


      The typically shared hosting environment consists of the following:

        Front-end servers – to route requests to their content locations

        Back-end web servers – to store and index the content

        Web management services – to enable the customers to publish and manage content speedily

    11) How do you ensure content security in IIS?


      We can ensure content security by using ACL (Access Control List). It provides allowing or denying permissions to the required identities.

    12) How do you make and restore backups of global server configurations in IIS?


      Using AppCmd, we can make and restore backups of global server configurations in IIS.

    13) What are the advantages of AppCmd in IIS7?


      The advantages of AppCmd are – it provides server control without the need for graphical administration tools. Besides, it enables us to automate server management quickly. Also, we don’t need to write any code.

    14) What extra care has to be taken while installing a native module?


      You need to install only the native modules that come from a trusted source. This is because any resource in the server worker process has unrestricted access to the native modules.

    15) What are the benefits of modular architecture in IIS7?


    Modular architecture

    16) What does Componentization mean in IIS?


      Componentization meant the availability of web server features as standalone components. You can easily add, remove, or replace a component.

    17) What are the different native modules of IIS?


      The native modules of IIS include – HTTP modules, Security modules, Content modules, Compression modules, Caching modules, Logging, and Diagnostic modules, and Managed support modules. All these modules are available with the full installation of IIS 7 and later.

    18) With which tool, you can debug IIS remotely?


      We can debug IIS remotely using the mavsmon.exe process, which belongs to MS Visual Studio 2005.

    19) What is the purpose of App pool recycling in IIS?


      The purpose of App pool recycling is to free up the memory, which is consumed by the applications in an app pool.

    20) Which are the protocols that IIS supports?


      The protocols that IIS supports include HTTP/HTTPS, FTP, FTPS, and SMTP, etc.

    21) What are the new features in IIS 8.5?


      The new features in IIS 8.5 include enhanced logging capabilities and dynamic site activation.

    22) What is the purpose of the Application Pool in IIS?


      Application Pool separates applications from each other and simplifies the management. It defines a group of settings for the worker processes, which carry out request processing for all the applications in a pool.

    23) What are the log files?


      Log files record different actions on a server, which includes the date, time, IP address, and volume of transmitted data.

    24) Can you point out the various permission settings that are available in the creation of Virtual Directory?


      The permission settings that can be set during virtual directory creation are as under:

      • Read
      • Write
      • Browse
      • Run Scripts
      • Execute

    25) What is a web garden and explain the process of creating a web garden?


      By default, each application pool runs with the aid of a single worker process(w3wp.exe). We can assign multiple worker processes to a single application pool. A web garden is nothing but an application pool which has configured on a single server by specifying multiple worker processes. Each worker process should have their own thread as well as their own memory space.

      For creating a web garden, we need to go into the application pool, right click on the application pool, click on the properties and then head into the performance tab. Once that’s completed, we need to go into the web garden section and increase the number of work processes. By default, this value is 1.

    26) Can you explain what recycling of application pool means?


      Recycling the application pool basically entails recycling the worker process (w3wp.exe) along with the memory used for the web application. Accordingly, there are two distinct types of recycling which are relatable to the application pool:

      • Recycling Worker Process – Predefined Settings
      • Recycling Worker Process – Based on memory

    27) What are various authentication methods using windows authentication which is provided by IIS?


      There are five distinct types of authentication methods usually provided by IIS which include:

      • Anonymous Method
      • Basic Method
      • Digest Method
      • Windows Integrated Method
      • Passport Authentication Method

    28) Can you explain the concept of Application pools in IIS?


      Application Pools are basically a group of web applications and websites. Any number of application pools can exist at one time. Moreover, they are used to isolate our web application for the purposes of providing us with better security, availability, reliability, and performance as they can keep running parallelly without disrupting each other’s functioning. DefaultAppPool is the name of the default application pool in IIS.

    29) Can you identify the different authentication modes used for IIS remote debugging process?


      msvsmon.exe is the tool used for IIS remote debugging. The IIS remote debugging process supports two distinct modes:

      • Windows Authentication
      • No Authentication
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    30) Please describe the various properties of App Pool in IIS.


      The App pool is IIS is characterised by the following four properties:

    • Recycling
    • Performance
    • Health
    • Identity

    31) What Is Web Garden?


      Configure multiple work process on one application pool in a web server is called as Web Garden.Application Pool can configure for multiple websites hosted in IIS.

    32) Which Is The Default Identity Of An Application Pool?


      Network Services

    33) Different Available Identity Of An Application Pool?


      For IIS 6.0 – NetworkServices,LocalService,LocalSystem

      For IIS 7.0 – NetworkServices,LocalService,LocalSystem and Application Pool Identity.

    34) What are the Default Iis Services?


    • www services (Worldwide Web)
    • FTP services (File Transfer Protocol)
    • SMTP services (Simple Mail Transfer Protocol)
    • NNTP services (Network News Transfer Protocol)

    35) Mention the Default Iis Port Numbers?


    • HTTP – 80
    • SSL – 443
    • FTP – 21
    • SMTP – 25
    • POP3 – 110
    • IMAP – 143
    • NNTP – 119
    • LDAP – 89

    36) What is the difference between application domain and application pool?


    Application DomainApplication Pool
    Application Domain is an ASP.NET concept which provides isolation for each ASP.NET application.Application Pool is an IIS concept which also provides isolation but at the process level.
    Application Domain is available only for ASP.NET applications.You can recycle the Application Pool in the IIS manager.

    37) What are the different Layers In Iis Architecture ?


      Two types of layers in IIS:

      Kernel Mode

    • HTTP.SYS
    • User Mode

    • Web Admin Service
    • Virtual Directory
    • Application Pool

    38) What Is The Key Role Od Http.sys In Iis ?


      HTTPS.SYS key component in Kernal level.It process the queue which hit the client request for each Application Pool depend on request.While create any new Application Pool IIS will register the Application Pool with HTTP.SYS.

    39) What Are The Security Authentication In Iis ?


      1.Anonymous ( Default Authentication in IIS runs under IUSER_servername )

      2.Integrated Windows Authentication

      3.Basic Authentication

      4.Digest Authentication

      5.Passport Authentication

    40) How To Open Iis Manager ?


    • From Run -> inetmgr
    • Start -> Programs -> Administrative tools

    42) What Is Web Farm In Iis?


      Hosting webapplication in multiple webservers using load balancer is called as Web Farm.To avoid the high load in single server this load balancer method will use to distribute the traffic to different server on same web application.

    Web Farm

    43) What Is Isapi Filter?


      ISAPI filters are DLL files used to modify the enhance functionality allocated by IIS.By default ISAPI filters run in IIS server.

      • change request URL or headers
      • perform custom authentication
      • Handle encryption and compression

    44) What Are Core Components Of Svchost.exe In Iis?


    • SVCHost.exe is the key component of www publishing service (w3svc) and Windows action Process(WAP)(WAP for start and stop the process).
    • W3SVC is the mediator for HTTP.SYS and WAP(windows activation process)

    45) What Are The Execution Permission For Virtual Directory?


    • None
    • Scripts Only
    • Scripts and Executable

    46) How To Take Iis Server Backup?


    • Open IIS and right click on Computer in IIS.
    • Select Internet Information Services.Now goto All Tasks Backup/Restore Configuration.
    • Click on create backup and give the backup name.

    47) Which Dll Is Used To Translate Xml To Sql In Iis?



    48) What Are Script Files In Iis?


      iisweb.vsb – Create,Delete,start,stop,list websites

      iisftp.vsb – Create,Delete,start,stop,List FTP sites

      iisdir.vsb – Create,Delete,start,stop,List Virtual Directories

      iisftpdr.vsb – Create,Delete,start,stop,List Virtual Directories under FTP root

      iiscnfg.vbs – Export and import IIS configuration to an XML file

    49) If There Are Multiple Worker Process Running On Iis, Then How Can You Attach A Particular Worker Process For Application ?


    • Search elements
    • Cache parameters
    • knowledge directory location
    • Request handlers

    50) How We Can Debug A Web Application Which Is Hosted On Iis ?


    • We can easily debug any web application that are hosted on IIS by using Attaching of Worker Process.
    • From Visual Studio IDE > Tools > Attach To Process
    • Select the particular Process, then start debugging.

    51) What Is The Use Of Enable Pinging Properties For Application Pool ?


    • IIS should periodically monitor the health of a worker process [ Idle or not , Time for recycle or not, All Worker process are running properly or not ] .
    • Pining means, Activation Process monitor Worker process performance, health, idle time etc.
    • By default it sets to 30s .

    52) What exactly means HTTP.sys in IIS?


      HTTP.sys is known as “HTTP Protocol Stack” or “Http Listener Process”

    • It is Implemented as a kernel-mode device driverIt is core component to receive and serve HTTP requests and passing them off to the worker processes.
    • When you create a Web site, IIS registers the site with HTTP.sys
    • Other than retrieving a stored response from its internal cache, HTTP.sys does not process the requests that it receives.

    53) What is IIS metabase? And In which format IIS stors configurations?


      IIS metabase is a special databse which is used to maintain the settings and configurations data for IIS. In simple term, it is a configuration base for IIS (Metabase.xml).

      • IIS 5.0 –> Metabse is in Binary.
      • IIS 6.0 & 7.5 –> Metabase is in XML.

    54) What are the main components of SVCHost.exe ?


    • Main components for SVCHost.exe are WWW Publishing Service (W3SVC) and Windows Activation Porcess (WAP) .
    • W3SVC is the mediator of HTTP.SYS and Windows Activation Process. Windows Activation Process maintain the worker processes.

    55) What are the different way that we can hosted site on IIS ?


      We can hosted site on IIS either creating Virtual Directory through IIS manager or Using Folder Web Sharing .

      Apart from that Visual studio provide some inbuilt features to host the site on IIS like using Publishing the web site , Using Copy web Tool or Creating Virtual directory during the creating the project by choosing Location as HTTP

    56) How does IIS process an ASP.net request ?


      When client request for an aspx pages, request comes to kernel level off IIS means to HTTP.SYS . HTTP.SYS receives the request and based on the application pool name [ Which is already registred with the HTTP.SYS ] it send the request to worker process. Windows Activation process works as mediator of them. w3wp.exe loads “aspnet_isapi.dll” files to start the HTTPRuntime . HTTPRuntime creates HTTPApplication objects and all request are passed through HTTPModule and finally reached to HttpHandler . This is the request pipeline. After end of Request pipeline ASP.NET Page lifecycle starts.

    57) What was the first version of IIS was introduced?


      Almost every version of IIS was released either alongside or with a version of Microsoft Windows. First version of IIS is IIS 1.0 and it was initially released as a free feature or add_on for Microsoft Windows NT 3.51.

    58) What are different security and authentication mechanisms of IIS?


      IIS 6.0 and later versions support and provide the following authentication mechanisms:

      • Basic access authentication
      • Digest access authentication
      • Client certificate mapping
      • IP security
      • Request filtering
      • URL authorization
      • Anonymous authentication
      • UNC authentication
      • .NET Passport Authentication (currently not available in latest versions)
      • Certificate authentication
      • Integrated Windows Authentication

    59) What are Log Files in IIS?


      In IIS, Log files are used to record a different events and actions which are occurs on your web server.

      A log files in IIS can provide differnt information such as

        –the date and time of the event

        –IP address involved in the event

        –The amount of data transmitted.

    60) What are IIS modules?


      You can use different IIS modules, which have different features for processing user requests. Some of most common IIS modules are as under:

      IIS Security modules: With security module you can do the security related task in the request processing pipeline. You can perform authentication-schemes, URL authorization, and filtering requests.

      Content modules of IIS: This module handle the tasks related to content in the request processing pipeline. Different requests like for returning a default-page when a client does not specify a resource in a request, static files and listing the contents of a directory.

      IIS-Compression modules: Used to perform tasks related to compression in the request-processing pipeline. Tasks like compressing responses, applying Gzip compression transfer coding to responses, and performing pre compression of static-content are achieved through compression module.

      IIS Caching modules: This module perform the caching related tasks such as cached content in subsequent requests for the same resource.

      Logging & Diagnostics modules: Used to perform tasks related to logging and diagnostics.

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    61) Is IIS more secure than Apache?


      IIS is a Microsoft product, as Windows operating system is more popular, therefore IIS has naturally exposed to security breaches. Due to this many hackers spend a good-deal of their time and efforts to exploiting & breaching it security. On the other hand Linux servers are consider more sercure as these operating system have an open source code, and more eyes on the improving critical aspects such as security. Apache-deployments, while perceived as being more secure, are no panacea for keeping web applications safe. You may required some security steps in order to harden your web server sercurity. Following are some secuirty steps for IIS web server installation:

      • Place the web content on a non system drive or partition
      • Block the ‘directory browsing’
      • Disable WebDAV to prevent remote-web content authoring
      • Configure application-pool identity for application pools
      • Restrict sensitive features to authenticated principals
      • Install SSL for “forms authentication”

    62) How to start and stop IIS Web server?


      You can use these commands in command prompt ” iisreset /stop” or simply “iisreset” to stop and start the IIS services. For stopping any individual website on IIS web server, you can simply right click on the website in IIS manger and then select “start” or “stop“.

    63) What is worker process in IIS?


      An IIS worker process is a windows process (w3wp.exe) which provides execution environment for running all web pages. This worker process is manages and answer all the request that are coming from the client hosts. ASP.Net perform or run all his function under the scope of the worker-process. In a simple word, worker process is the heart of ASP.NET (Web Application) which runs and handles all the request received from client system on IIS. You can find the worker process in the Web Server Home Features view, go to the IIS section.

    64) What is IIS pipeline?


    IIS pipeline
    IIS pipeline

    65) How does IIS handle multiple requests?


      IIS uses worker threads. Each worker thread is responsible for execution of a request per thread. If all the worker threads are full, the next request will have to wait for a worker thread to be free before it can be processed.

    66) How do I make concurrent users in IIS?


      Seeing the Number of Active User Sessions on IIS Site with the Performance Monitor Tool. Press Windows + R button. Type perfmon and hit the Enter button. Now, you have to add the relevant counters for seeing the number of active user sessions.

    67) How do I monitor traffic in IIS?


    • Perform HTTP Testing. By setting up a simple HTTP check that runs every minute, you can get a threshold, which you can use to determine whether the site is up or down.
    • Use Performance Monitor.
    • Use Task Manager.
    • Use Event Viewer.
    • Use Recommended Counter Monitors.

    68) What is maximum URL segments in IIS?


      The default value is 4294967295 . Optional uint attribute. Specifies the maximum number of segments permitted in a URL. The default value is 32 .

    69) Where are IIS logs stored?


      IS log files are stored by default in the %SystemDrive%\inetpub\logs\LogFiles folder of your IIS server. The folder is configured in the Directory property on the Logging page for either the server or an individual site.

    70) How do you optimize IIS?


      Apply IIS configuration options to improve IIS performance

    • Log only essential information or completely disable IIS logging.
    • Disable IIS ASP debugging in production environments.
    • Tune the value of the ASP Threads Per Processor Limit property.
    • Tune the value of the ASP Queue Length property.

    71) What is Maxurlsegments?


      This test groups transaction URLs based on the URL segments count configured for monitoring and reports aggregated response time metrics for every group. Using this parameter, you can specify the number of URL segments based on which the transactions are to be grouped.

    72) How do I enable request filtering in IIS 7?


      Open IIS Manager and select the level for which you want to configure request filter. In Features View, double-click Request Filtering. In the Actions pane, click Edit Feature Settings. In the Edit Request Filtering Settings dialog, edit the settings as desired, and then click OK

    73) What are Handler Mappings in IIS?


      Handlers are the ones that process requests made to sites and applications. Handlers map to resources on the Web server and generate responses for requests. IIS determines which controller to use based on the ordered list of handler mappings configuration when a user requests any file from the server.

    74)How do you check the unidentified XML elements and then install the relevant IIS modules?


      IIS can’t identify the XML elements of the modules that are not installed. For example, IIS URL Rewrite module.

      • Delete the malformed XML element from the ApplicationHost. config or Web. config file.
      • Check the unidentified XML elements, and then install the relevant IIS modules.
      • Install URL rewriting module.

    75) What are the web.config files?


    web.config files
    web.config files

    76) How do you create alias name for website in IIS?


      – Track-It! 11.x.

      – Open Internet Information Services (IIS) Manager.

      – Expand Sites.

      – Right click on ‘Default Web Site’

      – Select ‘Edit Bindings’

      – A ‘Edit Site Binding’ window will open, enter the desire alias in ‘Host name:’ section and hit OK.

    77) What is Digest security?


      Digest authentication is a method of authentication in which a request from a potential user is received by a network server and then sent to a domain controller. The user must then produce a response, which is encrypted and transmitted to the server.

    78) How do I change the hostname of a website in IIS?


      In the IIS manager, right click on Sites, click Add Web Site.. and enter the site name, physical path and hostname as www.mywebsite.com, as shown below. This will create a website on the local IIS server. Now, we want to use http://www.mywebsite.com instead of the localhost url.

    79) How do I map a domain in IIS?


      Add the additional domain name in IIS:

      • Step 1: Open Internet Information Services (IIS) Manager.
      • Step 2: Locate your website and select it.
      • Step 3: Click ‘Bindings’ on the ‘Actions’ pane on the right side.
      • Step 4: Click the ‘Add’ button in the ‘Site Bindings’ window.

    80) What is site binding in IIS?


      When working with a website a “binding” is the combination of protocol (http, ftp, https, etc.), IP address, TCP/IP port and host name– which is basically a domain name. … The binding is then associated with a website which allows IIS to properly route incoming traffic to the correct site.

    81) What does all unassigned mean in IIS?


      “All unassigned IP addresses” means all IP addresses not explicitly assigned to other sites. You have two sites on the same server. Site A is bound to a specific IP address. If you bind site B to “all unassigned”, it will not listen on the same IP address as site A, because that address is already assigned.

    82) Is it possible to change error content in IIS?


      You can add custom error messages to IIS by adding an element to the element in the Web. The element also can contain an errorMode attribute that you can use to control the level of detail that IIS returns to a browser when an HTTP error occurs.

    83) How do you turn off custom errors in IIS?


    • KB-1178 How to disable custom error pages on IIS
    • Navigate to the site on IIS.
    • Select Error Pages and then Edit Feature Settings.
    • Make sure only “Detailed Errors” is enabled.
    • Back in the site in IIS, select . NET Error Pages and then Edit Feature Settings.
    • Set the value to Off.

    84) How do I fix 404 error in IIS?


      To resolve this problem, verify that the file requested in the browser’s URL exists on the IIS computer and that it is in the correct location. Use the IIS Microsoft Management Console (MMC) snap-in to determine where the file requested must exist in the IIS computer’s file system.

    85) What are the implications of running ISAPI filters?


      ISAPI filters are DLL files that can be used to modify and enhance the functionality provided by IIS. ISAPI filters always run on an IIS server, filtering every request until they find one they need to process.

    86) How do I create a subfolder in IIS?


      Go to the IIS management console (Type inetmgr on run as tab and click enter), create New website, select the web site directory to the folder you have the document index. html. Once you configure IIS, you can access the subfolders within the virtual directory.

    87) What is ISAPI module used for?


      ISAPI filters are libraries loaded by the IIS web server. Every incoming request and outgoing response passes through the filters, and they’re free to perform any handling or translation they wish. They can be used for authentication, content transformation, logging, compression, and myriads of other uses.

    88) How do you point IIS to a folder?


    • Launch IIS Manager.
    • Right click the Default Web Site and navigate to Manage Website > Advanced Settings.
    • Under Default settings, update the physical path to point to the folder where the app resides.

    89)What is the main function of ISAPI?


      (Internet Server API) A programming interface on Internet Information Services (IIS), Microsoft’s Web server. Using ISAPI function calls, Web pages can invoke programs that are written as DLLs on the server, typically to access data in a database.

    90) What is IIS Geeksforgeeks?


      IIS stands for Internet Information Services (IIS, formerly known as Internet Information Server) IIS is a web server software package designed for Windows Server. … IIS is used to host an application over Web Server and is accessible from client systems via a web browser.

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    91) What is difference between Web Farm and Web Garden?


    Web Farm
    Web Garden
    After developing our asp.net web application we host it on IIS Server. Now one standalone server is sufficient to process ASP.NET Request and response for a small web sites but when the site comes for big organization where there an millions of daily user hits then we need to host the sites on multiple Server. This is called web farms. Where single site hosted on multiple IIS Server and they are running behind the Load Balancer. All IIS Request process by worker process ( w3wp.exe). By default each and every application pool contain single worker process. But An application pool with multiple worker process is called Web Garden. Many worker processes with same Application Pool can sometimes provide better throughput performance and application response time. And Each Worker Process Should have there own Thread and Own Memory space.

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