IIS sending different user page - asp.net

I have a problem that appears while using concurrent users in IIS/.Net 3.5.
I am logged in using two users to the same server (user1, user2), both are using different computers. If I press on a link to one page using user1 and immediately on the same link to the same page using user2, I receive the sent page to user1 on both computers.
It seems that IIS is caching the requests and sending it to both computers even though that both are logged in using different accounts.
This never happens if you wait a bit before doing that. Is there any specific IIS configuration that caches those requests? How can I link it to per account instead to all? At worst case, how can I disable it?
Any tips are highly appreciated.

ASP.NET has a configurable/extensible output caching mechanism.
You can configure/disable the stock page output caching in web.config, or write your own custom output cache provider and refer to that in web.config.
There's information about it here.

Related

Application uses anonymous authentication even though it is disabled in IIS

I have a diagnostic web application hosted in IIS7 that has Windows Authentication enabled and Anonymous auth disabled. This application generated some kind of a report where it includes information about what kind of authentication was used to view the site. Every time I browse to this site I get a message that I connected using Anonymous authentication which for me is unbelievable. The report works fine (tested on other machine) and the fact is that I do not get a credentials popup. How is this possible and how can I fix this?
First, i'm not knocking your diagnostic application, but it may be worth looking at the IIS logs (or indeed switching them on for your site) to see what IIS thinks is going on. If you're not familiar with IIS logs, I'd suggest writing them in Microsoft format (at least while you're sorting this problem). One of the key fields you get is the user id. If you really are hitting the pages anonymously, this id will be the id you configured to field anonymous requests. Otherwise, it will normally be the calling user's id (at least in a simple scenario).
Second, how many sites are you running? Are you sure you're going in through the expected site? Or maybe you're hitting the default site instead?
Third, bear in mind that authentication can be set at the site level but anso at the page level. Are you sure one isn't overriding the other?

Creating a cookie using ASP.net

I have a sharepoint webpart where I have links to go to different web sites to which login is required. Therefore, I think i need to log the users on before redirect them into deep pages in that site, therefore I think i need to set up a cookie to that web site when the web part is loaded (by using the user credentials of the user's active directory information).
How can I achieve this requirement with out opening up a new browser window? (Though I have used a client side script, it pops up a new browser window)
Any help is highly appreciable...
Thanks
If you are referring to "different web sites" as sites having completely different URL's, then it's probably not possible without SSO system.
The reason is that it's impossible to read/write cookies from other domain in web environment, i.e. pre-login the users like you are saying.
If all the sites are inside same domain, like mycompany.com for example, and different sites are in abc.mycompany.com or mycompany.com/subsite, then yes, you can set the cookie. See top section here http://www.15seconds.com/issue/971108.htm
A simple way to implement SSO is by implementing method described later on in same article.
in the "Requesting Cookie from Another Domain". This is not a very secure method though, but can be done if you restrict it properly to specific slave domains. And obviously all the slave sites have to be modified, as with any SSO implementation.

Request.ServerVariables not updated when simultaneous login from 2 machines

I'm using IIS 7.0 on WS2008.
I've implemented a simple login page that redirects to another simple page showing the Request.ServerVariables key/values.
I'm using the built-in SQL membership provider.
The website is on a DEV machine and there are no users on it.
When I login at the same time with 2 different users from 2 different locations (2 different public addresses) then one of the Request.ServerVariables page is the same as the other.
That includes the client IP address which is then completely wrong.
The authentication as well as the other cookies are wrong as well.
I checked the IIS log and it shows the correct client address as well as the correct login name.
If I then reload the wrong page I get the correct data.
Is there some concurrency issue in ASP.NET? I disabled the session and caching but I still get the same behaviour.
Cheers.
We had exactly the same issue when we accidentally cached too heavily on the IIS. The website simply returned whatever it had returned before.
Take a look at the site settings and see if you have any settings in the "Output Caching" of your website.

ASP.NET_SessionId cookie value does not allow multiple logins to the same web application from the same pc

We have a web application running on ASP.NET 3.5. It is viewed by the world as one URL but in reality there are multiple IIS boxes hosting the application controlled by a load balancer.
My problem is that it is a sensitive application with strict security controls around it, and that post authentication if you open another browser to the same application and log in as someone else, the second login overwrites the first logins' session id value in the cookie, and then the first window crashes.
Any idea how I can get around this?
The session ID is placed in the cookie. If another browser window is opened and starts a second session the ID in the cookie will be replaced.
Also, logins should not be controlled via the session cookie. There is a Forms Authentication cookie for that purpose which is more secure as I recall.
Most web applications only allow one session per PC. Try logging into Yahoo Mail, Amazon or Ebay twice on the same machine and you will find the same problem. So ASP.NET is pretty much designed around the idea that there is one login per PC. Although, if you have multiple browsers installed on a machine, you can generally log into apps more than once because each browser keeps its own cookie collection.
edit: You might want to try cookieless sessions, in theory they might allow multiple sessions per PC, although I haven't tried it. But cookieless sessions come with plenty of problems and limitations of their own.
In short, there may be some hacky way to do what you want to do, but it will probably be fiddly and cause other problems elsewhere, because what you are asking for goes against the grain of ASP.NET's core design.

Double Logon for some users of an ASP.Net WebForms app

I have an asp .net webforms app that uses forms authentication. For a small number of users we have a problem where they log in, they navigate to a couple of pages and then they are asked to log in again. Once logged in for a second time they seem to be able to stay logged in as expected. They shouldn't be asked to login the second time.
This is a single server, no web farms, nothing tricky.
This only happens to a few users, but it does seem to be all users from the same building. I am unable to replicate this and at this point might even start to deny that t was happening if one of our trainers hadn't watched it happen to a couple of customers.
Has anyone else seen anything like this?
I am also seeing a lot of "Membership credential verification failed." errors in the event log. This may be related, but all the googling I've done seems to point to web farms and the like, not a single server.
UPDATE
There is no proxy server, the IIS server and the browser (IE8) are both on the same machine.
The AV software installed is Symantec Endpoint, on one machine, on the other the user didn't have any AV at all (AV Fail!).
The browser is IE 8 with no frills, not a single addin that didn't come with the default installation.
Both session and user login time-outs are set to 30 mins and the problem happens within 1 min of the user logging on.
Logging shows the user to only have one IP address.
I have tried the sessionMode in all it's variations, this doesn't seem to make any difference.
Something has to be causing ASP.NET to think these users have new sessions or their authentication cookie is getting invalidated. Here a a few things I can think to check:
Are the users accessing the site through a proxy server? One of our customers has a proxy that will sometimes close all open connections causing ASP.NET to see the session as new.
Could an overly agressive anti-virus, anti-spyware product be "eating" the session authentication cookie?
Do they have a cookie manager browser add-in that is causing the authentication cookie to disappear or change?
Sounds basic but I've seen this happen because of site timeouts being set too short. If the user sits on the page for longer than the timeout, they will be forced to logon again. And this could be specific to a page when that page presents a large amount of data that takes a while for them to go through.
One other thing I just thought of, have you allowed multiple worker processes for the ASP.NET process (aka web gardens)? If so, the same constraints as with a web farm would apply for authentication.
Crack open Fiddler from the problem user's PC and see what's getting passed in the headers. My bet is on a proxy server and or networking issue.
Are the users possibly coming from a dynamic ip address? I've seen problems where the users sessions get messed up because the IP address that they're accessing the site from changes for some reason.
Are the people this is happening using a browser that's somehow different (different browser, different version, different extensions)? That could be a clue.
In general, when the problem is somewhat reproducible or at least predictable, I use Http Fiddler. Install it on a client machine, turn it on, and start browsing (this works via a system proxy - so it'll work for firefox, IE and any other proxy-supporting browsers alike). Fiddler will record all http traffic between client and server, and you can then peruse such a session later on to find any oddities.
It's a long shot, but one thing I've seen happen occasionally that can lead to these sorts of unpredictable errors is scripting parallelization issues: sometimes buttons + links have onclick handlers which cause a post-back. If you have several such handlers that fire on the same event - in particular when the default event still fires additionally to your custom onclick or whatnot - you may be causing several postbacks when it appears to be just a single postback. That can cause all kinds of unpredictable weirdness as it's not entirely clear which request ends up "winning" - and some odd errors may cause a session to terminate. Since this behaviour is very browser + network latency sensitive, it seems quite unpredictable when it occurs.
Delete the cookie on the client PC's that are playing up
ASP.NET Forms Authentication can redirect users to the login page if they do not have the credentials to access a specific page. It does this so that users who may have more than one login are given the opportunity to login with another account which may have the appropriate access. Basic question I know, but are the users using the same credentials the second time they log in?
Its possible that you have don't have specifically specified asp.net to use cookie based session but are allowing either cookie or cookieless sessions.
In the later case the session id is embedded in the Url. The type of issues you are experiences might be explained by that. Basically depending on how you define your links, some of them would not get the session id, so the user would get a new session when using those links - or maybe during a redirect. That could explain why at specific parts of your site the users loose their session.
If you have the mixed mode enabled, try setting it to only cookieless and go through your site.
Update: Based on the extra info posted there is surely more info needed for it. Some extra things to check:
Are you using subdomains, if that's the case the cookie might not be configured to allow that and that doesn't fail in all environments.
If you are using in-process session, make sure there isn't a bug in the application causing it to restart the process
Maybe what's causing it to ask for login again is an authorization check, and you have an issue on some roles related code
Is it possible that the user is just opening a separate window? ;)
To rule out the possibility of the browser or a browser addon messing things up, have you checked their User Agent strings? If they are randomly distributed it might not cause the problem, but if they're all the same, this might be a hint too.

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