Question: What is a web-farm and how do u manage session in web-farm?

Answer: A web-farm is group of webservers hosting a single web application.
Sice the web application is shared across multiple servers, session info can
not be stored in process memory of any of servers. It should be stored in a
centralizes database or state machine.

Question: How do you preserve persistent data, such as simple variables, in a Web
application?

Answer: You can preserve data in state variables, such as ApplicationState,
SessionState, or ViewState.

Question: How cookieless session works in ASP.NET?

Answer: In cookieless session session id gets embedded in URL automatically. So
when url request is made, session id is stripped from URL by ASP.NET
And is used to identify session information belonging to user.


Question: Does cookieless session works when absolute paths are specified ?

Answer: No cookieless session does not work with absolute paths. It works only with
relative path.

Question: Is it possible to protect view state from tampering when it's passed over an unencrypted channel?

Answer: Yes. Simply include an @ Page directive with an EnableViewStateMac="true" attribute in each ASPX file you wish to protect, or include the following statement in Web.config: his configuration directive appends a hash (officially called the message authentication code, or MAC) to view state values round-tripped to the client and enables ASP.NET to detect altered view state. If ASP.NET determines that view state has been altered when a page posts back to the server, it throws an exception. The hash is generated by appending a secret key (the validationKey value attached to the element in Machine.config) to the view state and ashing the result. An attacker can't modify view state and fix up the hash without knowing the secret key, too.


Question: How do u synchronize access to Application variables by multiple threads.

Answer: Use Application.Lock and Application.Unlock before accessing Application

Question: How do u cache a web page in ASP.NET?

Answer: <%@ outputcache duration=”60” varybyparam=”none”>

Question: What is difference between following statements
1 - <%@ outputcache duration=”60” varybyparam=”none”>
2 - <%@ outputcache duration=”60” varybyparam=”*”>
3 - <%@ outputcache duration=”60” varybyparam=”name”>

Answer: Statement 1 caches only one version of the page irrespective of querystring
parameters. Statement 2 caches multiple versions of same page I any of
quewrystring parameter varies. Statement 3 caches multiple versions of the
page for different values of parameter xyz.


Question: What is difference between canche.insert and cache.add method

Answer: The Add and Insert methods have the same signature, but there are subtle
differences between them. First, calling the Add method returns an object
that represents the cached item, while calling Insert does not. Second, their
behavior is different if you call these methods and add an item to the cache