The IIS 7 Team Rocks!

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I recently wrote about some 503 Service Unavailable Errors with IIS 7 that had me completely stumped. I tried everything I could think of to no avail.

Fortunately, a few of the members of the IIS 7 team stepped in to help. First, I received an email from Bill Staples, the group program manager of the IIS 7 team, kindly offered his assistance.

Meanwhile, Mike Volodarsky, a Program Manager on the IIS team in charge of the IIS 7 Web Server engine started offering help in my comments. Mike has a great blog with many useful troubleshooting tips for IIS 7. Highly recommended.

Mike brought in Chun Ye, a member of the http.sys team, who helped me get to the bottom of the problem. Here is the command he had me run.

netsh http show urlacl

The result showed that I had reserved http://+:80/ which takes precedence over all other URLs on port 80.

Reserved URL : http://+:80/
    User: METAVERSE\Phil
       Listen: Yes       Delegate: No

The solution was to run this command:

netsh http delete urlacl url=http://+:80/

Which removed the reservation.

To be honest, I have no idea why that reservation exists. Most likely it was something dumb I did a long time ago trying to debug some other long forgotten problem. I probably forgot to revert my change or didn’t even realized I had made a change.

I don’t have a real deep understanding of http.sys reservations. What I do know about it mostly comes from this post by security guru Keith Brown.

In any case, many thanks to the IIS 7 team for your help. You rock in my book.

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24 responses

  1. Avatar for Scott
    Scott May 21st, 2007

    Would my suggestion of trying to bind something to port 80, like Apache, have helped in this case?

  2. Avatar for Haacked
    Haacked May 21st, 2007

    Not sure. It would've failed I believe. But I wouldn't have thought, "Oh! Must be http.sys reservations!" ;)

  3. Avatar for Rick Strahl
    Rick Strahl May 22nd, 2007

    I'll second that the IIS team has really been all out in scouring blogs and pitching in with any issues at all! Both Bill and Mike have bailed me out a couple of times as well and posted follow ups to questions with extended blog entries which is awesome. Kudos and a big thank you to those guys!!!

  4. Avatar for Joe Brinkman
    Joe Brinkman May 22nd, 2007

    Oh sure. Just show off your inside connections. Don't mind us who must suffer our Vista nightmare's in obscurity ;-)
    I do have to commend Microsoft for spending more time in the community the last year or two. Compared to 3 or 4 years ago, I think Microsoft has gotten more in touch with what is going on and is actively out working in the community to try and identify and solve our problems, if not always on a personal level, certainly on a global one.

  5. Avatar for Haacked
    Haacked May 22nd, 2007

    @Joe - ha ha. No inside connection. I posted it on my blog and they found it.

  6. Avatar for Mike Volodarsky
    Mike Volodarsky May 27th, 2007

    Thanks for the warm regards - glad to help out :) I have to say, a lot of time, we take something away that helps us improve IIS7 or understand where we can do more to help people use it.
    Please be sure to blog or post your issues on, and we'll try to help you out ... especially if its something tricky that is not already covered by a google, I mean, MSN search :)

  7. Avatar for RBertora
    RBertora August 21st, 2007

    Help Please!

    I followed the above suggestions and ran:
    netsh http show urlacl
    and found I had:
    Reserved URL : http://+:80/wsman/
    Reserved URL : http://+:80/Temporary_Listen_Address/
    trying to remove these I get the error:
    URL reservation delete failed, Error: 5
    The requested operation requires elevation.
    Any ideas?
    Also I have created a new website on Port 8001 (not reserved), and get the same damn error in the browser:
    Service Unavailable
    HTTP Error 503. The service is unavailable
    Any ideas?

  8. Avatar for Me
    Me September 4th, 2007

    I didn't erase reservation on port 80... and tried to put my web on port 133... so i acess "http://localhost:133" and what a surprise i keep on having the same error "HTTP Error 503. The service is unavailable." so this demonstrates that's not the solution, maybe it is to your problem not to mine

  9. Avatar for Scott
    Scott February 26th, 2008

    I am not sure if I would say that the IIS 7 team rocks. If they rocked there would have been an error in the event log explaining exactly what was going on. However *you* rock for posting this, because I had a very similar problem and you helped me to fix it. I was converting from a WCF Service hosted in an NT Service (which needs the namespace reservation) to hosting it in IIS which apparently barfs with a 503 and no event log error if there is a namespace reservation. What was a little wierd was that the app pool was running under Network Service (NS), and that was the account the namespace reservation was under:
    Reserved URL : http://+:80/Echo/
    Listen: Yes
    Delegate: No
    SDDL: D:(A;;GX;;;NS)
    I even considered that the namespace reservation could be causing it, but for some reason I dismissed the thought.
    Anyway thanks a ton for your help, if only I had read this 3 hours ago...

  10. Avatar for Joe Walters
    Joe Walters September 23rd, 2008

    I think I can confirm that the reservation was not something you did because this fixed it for me too and I have never touched anything like that directly. My guess that this is the default setting for something or other.
    What I know about networking and ports etc. would fit inside this O but I have spent two full days trying to resolve this.
    Thanks a bunch .........

  11. Avatar for John Clark
    John Clark October 30th, 2008

    Just wanted to say thanks - I've just spent a day tracking a bizarre problem which had the same symptoms, and happened to be a result of the same thing. You've saved my Friday.

  12. Avatar for Jimbo
    Jimbo October 26th, 2010

    I got the same problem as RBertora - IIS7 seems to have crippled itself. No matter what port you start a website on it gives that same dam error :(
    IIS Team?

  13. Avatar for Ben
    Ben August 2nd, 2011

    Hi thanks for posting the trick. But as some other people here, the trick did not fix my problem on my windows 7. I swear IIS worked before and now nothing works! Any other solutions?

  14. Avatar for Jack
    Jack August 30th, 2011

    you also get "503 Service Unavailable" if the application pool is stopped

  15. Avatar for Samir
    Samir November 15th, 2011

    So glad I read all the comments! Somehow the application pool for one of my sub domains was stopped and Jack's comment saved me.
    This might be basic for some but I come from a LAMP background where (imho) it's much easier to investigate issues like this. I don't know how long I might have wandered around without that last comment.
    Developing/Maintaining complex web apps is hard enough without having to deal with issues like this... I miss linux+apache ;-).
    Thanks to everyone here!

  16. Avatar for Rafa
    Rafa March 28th, 2012

    If that also doesn't work you have to give System Full Access to your Users Folder. That did the trick for me. I don't know why it can't create DefaultAppPool IIS APPPOOL in that folder but now it does.
    Hope it helps

  17. Avatar for Fernando Alonso
    Fernando Alonso April 25th, 2012

    This worked like a charm for me! thanks!!!

  18. Avatar for TorstenR
    TorstenR July 15th, 2013

    This just helped me today to solve the exactly same issue on my machine today!

  19. Avatar for haacked
    haacked July 15th, 2013

    Ha! Hi Torsten! I hope you are doing well and glad my post could help even after all these years. :)

  20. Avatar for JB
    JB October 17th, 2013

    Saved my bacon Phil! After reading a bazillion other posts saying I should just recycle the app pool yours is the only one that worked.

  21. Avatar for davesters81
    davesters81 January 7th, 2014

    WOW, this actually worked! I have been messing with this stupid thing for days and stumbled upon this post. Even though I am using port 8080 instead of port 80 and am on IIS 8.5.

    I had a reservation in my urlacl for this same port 8080. I was running these commands telling myself "This probably won't even do anything". but then it Worked! Amazing that this still works almost 7 years later.

    Thanks for posting this and props to the IIS team!

  22. Avatar for Johnny T
    Johnny T November 27th, 2014

    Thanks! This fixed my problem.

  23. Avatar for Jim Prucha
    Jim Prucha April 9th, 2015

    Thanks so much for sharing this!! Fixed my issue. Never would have happened if I personally installed SQL Server as I wouldn't have installed the Report Server as we do not use it... Lesson learned.

  24. Avatar for Mrinal
    Mrinal October 8th, 2015

    Thanks, It helped.