Unable to connect to the ASP.NET Development Server RRS feed

  • Question

  • User1849276799 posted


    I downloaded VWD 2008 Express, and whenever I try to run any ASPX page to debug it or test it .. it gives me the following message in a messagebox:

    "Unable to connect to the ASP.NET Development Server"

    Anyone has an idea about it?

    by the way VWD2005 works fine!

    Monday, December 3, 2007 9:34 PM

All replies

  • User-1237418611 posted

    me too,look at the ports they are not the same,when they are same then I have that error that you write..I have that error with visual studio 2008,but visual studio 2005 works just fine...

    look at the ports they are not the same


    Saturday, February 9, 2008 4:15 AM
  • User-1363174918 posted

    This thread may be useful http://forums.asp.net/t/1209387.aspx 

    Saturday, February 9, 2008 1:38 PM
  • User-1237418611 posted
    I have windows xp pro sp2 not vista operating system..
    Saturday, February 9, 2008 2:51 PM
  • User385002971 posted

    Hi Mosabama,

    You probably have already solved as your post is about one year old but it may be useful to share my experience with other people who have the same issue, as there is no much on the web, and as someone said it is quite a rare issue. In my opinion there is no bug, problem or anything like that, simply a conflict.

    I have had the same problem and it was due to the fact I had Oracle® Database Express Edition 10g installed on my machine. Oracle once installed, gives you the possibility to access the XE database homepage directly via your browser. The url used to access the XE database homepage typically takes one of the following forms:

    As you can see your port 8080 (HTTP alternate port) is busy. I suspect that the standard Development Server for VWD 2008 for default works on the same port, differently for example from VS 2005 which random and automatically select one of the unassigned port for you. Well I could uninstall Oracle or stop its XE services on my machine but I needed the DB GUI for another project so I worked round and forced my project to use a Development Server which works on another port and I did this way:

    Step 1: Select the “Tools->External Tools” menu option in VS or Visual Web Developer.  This will allow you to configure and add new menu items to your Tools menu.

    Step 2: Click the “Add” button to add a new external tool menu item.  Name it “WebServer on Port 8010” (or anything else you want).

    Step 3: For the “Command” textbox setting enter this value: C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\WebDev.WebServer.EXE (note: this points to the web-server that VS usually automatically runs).

    Step 4: For the “Arguments” textbox setting enter this value: /port:8010 /path:$(ProjectDir) (or any port you like)

    Step 5: Select the “Use Output Window” checkbox (this will prevent the command-shell window from popping up.


    Once you hit apply and ok you will now have a new menu item in your “Tools” menu called “WebServer on Port 8010”.  You can now select any web project in your solution and then choose this menu option to launch a web-server that has a root site on port 8010 (or whatever other port you want) for the project.

    You can then connect to this site in a browser by simply saying http://localhost:8010/.  All root based references will work fine.


    Step 6: The last step is to configure your web project to automatically reference this web-server when you run or debug a site instead of launching the built-in web-server itself.  To-do this, select your web-project in the solution explorer, right click and select “property pages”.  Select the “start options” setting on the left, and under server change the radio button value from the default (which is use built-in webserver) to instead be “Use custom server”.  Then set the Base URL value to be: http://localhost:8010/


    Obviously I don't know if this is the problem you had but definitely it is something similar, essentially the problem should be that the same port used by your Development Server is not available because it is already used by another web server.



    Rosario Carbone


    P.S. I used 8010 in my example as this port normally is unassigned. 


    Tuesday, February 26, 2008 5:15 AM
  • User-275548861 posted

    check your firewall settings maybe you forget to give permission

    Thursday, February 28, 2008 11:04 AM
  • User681754728 posted


    I have Windows Vista Home Premium Edition.  I installed VWD 2008 and after creating a test.aspx, I tried to start the server.  I got this same error.  Horrible!!!  It is a killer.  On my machine it connects to port # 49716.  I tired spending several hours, googling and tried all options.  I could not get the server running.

     Any suggestions


    Friday, February 29, 2008 10:31 AM
  • User681754728 posted


     Finally I found the problem.  I edited the hosts file  which had an entry for local host like ::localhost.  I commented this line out and it started working.

    Thursday, March 6, 2008 7:48 AM
  • User-1335005129 posted

    I had the same issue w VS2008. My solution wasnt found on the web. After using sysinternals process monitor I found the path VS was using to execute the server was incorrect. I guess MS didnt take into account my system was a 64bit system. So I had to move my DevServer folder to C:\Program Files\Common Files\microsoft shared\DevServer dir. In its present C:\Program Files (x86)\Common Files\microsoft shared\DevServer it was usless since MS was looking in the wrong location.

    I hope this saves some other poor sap the time it took me to figure it out.


    Monday, June 16, 2008 5:13 PM
  • User-1237418611 posted

    I solved my problem,I uninstalled my eset nod 32 security suite that was blocking him and now everything woks perfect...

    Tuesday, June 17, 2008 11:45 AM
  • User649307680 posted


    I had this problem too in my WinXP SP2. I had eset smart security and I have blocked my MSVS 2008 in its firewall's Interactive Mode.

    I Fixed it in this way [There is no need to uninstall your smart security). :

     1. Right Click on my ESET Icon in traybar.

     2. Choose Advance Setup menu.

     3. On the opened window on the left side choose Personal Firewall -> Rules and Zones.

     4. On the Right side in the Zone and Rule editor part Click  SETUP.

     5. Select Microsoft Visual Studio 2008 -> Deny Communication for devenv.exe

     6. Right Click on it and select EDIT

     7.  Set Direction to Both and Action to Allow.

     8. Click OK.


    Enjoy it. [Yes] [Idea]

    Thursday, June 26, 2008 2:56 AM
  • User248204183 posted


     I'm having the same problem. Tried everything. Editing the hosts file, adding the webserver to a different port. Same thing.

    I just created an asp.net ajax application.

    I did nothing other that typing hello world on the default page

    -> Hit f5 -> Waited for the asp.net webserver icon to show in the tray

    -> waited for some 6 min and was greeted with a dialog - unable

     PS: If I double click on the webserver icon in the tray and click on the link, the page loads fine. The issue is getting vs to load it


    When I changed the port to 8010 using the guidance above I get the error message - The directory "XXX"  does not exist.


    I've checked my firewall settings and the webserver is not blocked.

    Wednesday, September 3, 2008 7:03 PM
  • User2006178999 posted

    I've only just skimmed this thread .. but i can't believe no one noticed that the ports where different!!! 


    Hope that helps, Marko Bozan.


    Sunday, September 14, 2008 12:41 AM
  • User-1363174918 posted

    Marco, do you have VS 2008 SP1 installed?

    Monday, September 15, 2008 1:12 PM
  • User-1363174918 posted

    Also, try setting a fixed, predefined port in project properties (properties window should have an option to switch off dynamic ports)

    Monday, September 15, 2008 1:27 PM
  • User-1237418611 posted

    I solved my problem long time ago,it was problem with my eset nod32 firewall,thanks for answering anyway....

    Monday, September 15, 2008 5:11 PM
  • User-1237418611 posted

    Problem solved long time ago....

    Monday, September 15, 2008 5:13 PM
  • User-1382472478 posted
    Good staff.
    Sunday, September 21, 2008 1:37 PM
  • User1154285617 posted

    I am ABLE to connect to my localhost asp.net developer server -- but i'd like my 2nd dev sitting next to the machine to be able to connect.

     In other words, I'd like another machine in the same NAT to be able to connect via http to my asp.net developer server. I'd like to do this to debug some issues I only see when running a client machine and a server machine on separate boxes. We are able to do it in practice by running our asp.net application on IIS, but I'd like to run the server process from within VS2008 so I can debug the issue in code.

     Any advice would be GRAND!


    Tuesday, October 7, 2008 2:50 PM
  • User-1363174918 posted

    You can't. Developmenr server is not available from outside the machine, it only listens on localhost.You may try using Cassini 2 instead http://www.ultidev.com/products/Cassini/

    Tuesday, October 7, 2008 3:17 PM