Tuesday, December 28, 2010

IIS Interview Questions

1. Use appcmd.exe to recycle the application pool from the command prompt.

2. appcmd.exe is the command line tool for IIS7, you will find this tool at following location :


3. To recycle your application pool use the following command:
appcmd recycle apppool /apppool.name:
Status Code Type of Code
100 Series - Informational
200 Series - Success
300 Series - Redirection
400 Series - Client Error
500 Series - Server Error
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.
In IIS, an anonymous user will be given with a user name of "IUSR_MachineName "
Step 1 : In the IIS (inetmgr), right click on the "Computer" icon under "Internet Information Services" . Click "All Tasks" and select "Backup/Restore Configuration".

Step 2 : Click on button "Create backup". Give Name for your backup file. If you want encryption enable encryption option and give UserName and Password and then click OK.
IIS 7.5
This can be change from Virtual Directory properties. First open Properties of Virtual Directory > GoTo ASP.NET Version Tab.

There we can have change the ASP.NET Version.
There are three Execution Permission available.
1. None
2. Scripts Only
3. Scripts and Executable
We can set the Session time out settings from the Virtual Directory for that site.

Right Click on Virtual Directory > Properties > Click on "Configuration" Button
Goto the "Option" Tab. There in Enable Session State Section you can configure the Session Timeout .
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.

For more Information :
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
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.
Yes. We can.
While creating Application Application Pool From IIS, there should have two option available first one is for Default Setting and Another is for Existing Setting as template.
We can select the second one and from the drop down listed below we can select any on the Application Pool as Template,.
Yes, We can directly host any site from the physical location of directory itself.

Right Click on Physical Folder > Properties > Web Sharing

There you need to select > "Share This Folder" Option Button. Then it will ask for alias name and other setting. Then Click on OK.

To Validate : Run > Inetmgr > Check there should an virtual directory with the same "Alias" name that you have given.

If there are already one Virtual directory exist it will showing you the error message while you providing the "Alias" name.
There are following reasons where we can use remote debugging
1. Your development server does not have IIS installed.
2. Development server and Build/Released/Hosting Server is different
3. Multiple user want to debug simultaneously.

Before Giving the Definition : you can say like this, Concept of Application pool has from IIS 6.0 .
Application pools are used to separate sets of IIS worker processes that share the same configuration and application boundaries. Application pools used to isolate our web application for better security, reliability, and availability and performance and keep running with out impacting each other . The worker process serves as the process boundary that separates each application pool so that when one worker process or application is having an issue or recycles, other applications or worker processes are not affected.
One Application Pool can have multiple worker process Also.

Main Point to Remember:
1. Isolation of Different Web Application
2. Individual worker process for different web application
3. More reliably web application
4. Better Performance
By default Each Application Pool runs with a Single Worker Process (W3Wp.exe). We can assign multiple Worker Process With a Single Application Pool. An Application Poll with multiple Worker process called Web Gardens. Each Worker Process Should have there own Thread and Own Memory space.

Generally its not recommended to use InProc Session mode while we are using Web Garden.
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 .
Visual studio having It own ASP.NET Engine which is capable enough to run Asp.net web application from visual studio. So we just click on Run button to start the application.
Now this is the scenarios of local environment. But If we want to host it on server from where all user can access the sites then IIS comes into the picture.

IIS provides a redesigned WWW architecture that can help you achieve better performance, reliability, scalability, and security for our Web sites. IIS can support following Protocol HTTP/HTTPS, FTP, FTPS, SMTP Etc. We need to host the site on IIS, when request comes from client it first hits the IIS Server, then the server passed it to ASP.NET worker process to execute. Then the response also passes to client via IIS itself.
Note only Hosting of Site we can create our FTP Server, SMTP Server using IIS itself.
There are different version of IIS available like 5.1, 6.0, 7.0 etc
WAP is the Controller of Worker process under a Application Pool. Windows Activation Process which is managed by the worker process by starting, stopping and recycling the application pool. When to start, stop and Recycle should be defined on Application Pool Settings. Activation Process is also responsible for Health Monitor of Application Pool during runtime.

FYI : Health monitoring setting can be easily found in Properties of Application Pool.
This is one of the most question in IIS. And along with that interviewer can as what is the different between Web farm and Web Garden ?

When we hosted our web Application on multiple web server under a load balancer call the Web Farm. This is generally used for heavy load web application where there are many user request at a time. So When Web Application is hosted on Different IIS Server over a load balancer, Load balancer is responsible for distribute the load on different server.

Please have a look into this :
Below are the Major Innovation in IIS 7.0
Components are designed as module and there are major change in administration settings.
FYI : You can find out many of them, just go thorugh Microsoft IIS web site.
We can set the Idle time out for an worker process from Application Pool Properties.

In Performance Tab of Application pool, we can set the Idle Time out of the worker process. This means worker process will shut down after that given time period if it stay idle. And will again wake up again if a new request comes.
We can set the default page for a web site from the Virtual Directory Setting.
How To :
IIS Manager > Virtual Directory > Right Click > Properties > GoTo Document Tab.

For IIS 5.1 > aspnet_wp.exe
For IIS 6.0 > w3wp.exe
NOTE: This is objective type question, Please click question title for correct answer.

NOTE: This is objective type question, Please click question title for correct answer.
NOTE: This is objective type question, Please click question title for correct answer.
NOTE: This is objective type question, Please click question title for correct answer.
IIS 7.0 having two types of application pool.

1. DefaultAppPool (Integrated)
2. ClassicAppPool
Just simply Run >inetmgr
Or we can open it from control panel > Administrative tools.
This is one of the more important question for experienced guys.

Please read this in details.
Yes. IIS Can have multiple web sites and Each and every web sites can have multiple virtual Directory.

Note : Here web sites means the Root Node.
This is used automatically register the .NET Framework with your IIS.

For more information :

Yes. This is one of the great features of msvsmon.exe . Each instance of the remote debugger has a unique server name.we can give an instance of the remote debugger any server name. Now multiple user can able to access the server instance.
Well, If there are multiple worker process running in IIS, it means I have to know the name of my application pool. Then I can run cscript iisapi.vbs script to find out the process ID and Application Pool name . Based on the process Id for particular application I have to attache the process from Visual studio IDE.
By running iisapp.vbs script from command Prompt.

Below are the steps :
1. Start > Run > Cmd
2. Go To Windows > System32
3. Run cscript iisapp.vbs
For IIS Remote Debugging msvsmon supported two authentication mode

1. Windows Authentication
2. No-Authentication
Tools is : msvsmon.exe

This is located at : Install path\Microsoft Visual Studio 8\Common7\IDE\Remote Debugger\x86
Application Pool Settings can be save as "XML" Format.

Right Click on Application Pool > All Task > Save Configuration to a File .

This will save all the settings of Application Pool as an XML file.We can make it password protected also.
IIS 7.0 .

Even Vista Home Premium and Ultimate edition is also having IIS 7.0
No. Every Web Application should have one Application Pool. Bydefault it is "DefaultAppPool ".
Below are the list of permission that can be set during virtaul directory creation
1. Read
2. Run Scripts
3. Execute:
4. Write:
5. Browse
Open IIS Configuration Manager
First of all Right Click on Default web sites > New > Virtual Directory .
Browse the Physical Path. Set the properites. Click on OK
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.

For more information Read this article :

For creating web graden we need to go to Application Pool, then Right Click on Application Pool > Properties > Goto Performance Tab

In Web Garden Section, increase the number of worker process. By default it is 1.
Session data store inside process memory of worker process [ w3wp.exe ] .
Anonymous authentication is the default authentication mode for any site that is hosted on IIS, and it runs under the "IUSR_[ServerName]" account.
Below are the commonly used IIS Security settings

1 Anonymous
2 Integrated Windows Authentication
3. Basic Authentication
4. Digest Authentication
5. Passport Authentication

For Set security permission you need to go to Virtul Directory > Right Click > Properties > Directory Security
Click on Edit Button .
HTTP.SYS is the kernel level components of IIS. All client request comes from client hit the HTTP.Sys of Kernel level. HTTP.SYS then makes a queue for each and every request for each and individual application pool based on the request.
Whenever we create any application pool IIS automatically registers the pool with HTTP.SYS to identify the particular during request processing.
IIS having mainly two layer Kernel Mode and User Mode

Below are the subsection of both of them.
1. Kernel Mode
2. User Mode
o Web Admin Service
o Virtual Directory
o Application Pool
ecycling Application pool means recycle the Worker process (w3wp.exe ) and the memory used for the web application.
There are two types of recycling related with Application pool

1. Recycling Worker Process - Predefined Settings
2. Recycling Worker Process - Based on Memory
Default Identity of IIS 6.0 is NetworkServices .
Which is having very minimum rights on your system. The user can only have the read access of the site.
IIS having three different Identity.
1. Local System
2. Local Services
3. NetworkServices
Though we can create new application pool IIS with different settings, but IIS having its own default application pool named : DefaultAppPool
Before answering this question you need to know what are the different IIS version is available in different OS. Below is the list of IIS version with different Operating system.
Windows Server 2008 - Windows Vista - Home Premium/ Ultimate - IIS 7.0
Windows Server 2003 - IIS 6.0
Windows XP Professional - IIS 5.1
Now based on your working experience you can say that you have worked on IIS 5.1 and 6.0 or only IIS 7. Etc.
Now, the next question that can asked after answering this question is “what is the difference between them ? ” – Well I will come with this later.

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