Fiddler not sniffing SOAP traffic from ASP.NET website

Question

So far I've been successfully using fiddler to sniff web service traffic from both test fixtures, console apps and web projects.

Today I noticed I am not able anymore to sniff that kind of traffic if I am running my web application (it's a ASP.NET website, hosted locally on IIS). I see all the local traffic but the web service traffic is just gone (the service is being hit as I do see the response debugging into the code).

I am still able to successfully sniff soap requests and responses from test fixtures or console apps in the same solution (exact same environment).

If it was a windows (I am on Win7) security update or the likes it would never work I guess (unless it affects only traffic routed through IIS).

What should I be looking for that could cause the emergence this behavior?

Any pointers appreciated!

NOTE: I can see local traffic, but not the SOAP request/responses to the web service which is not hosted locally anyway (it's a sandbox another team is providing)

EDIT: This bit of configuration did the trick (found on Rick Strahl's blog)

  <system.net>
    <defaultProxy>
      <proxy
        usesystemdefault="False"
        bypassonlocal="True"
        proxyaddress="http://127.0.0.1:8888"/>
    </defaultProxy>
  </system.net>

Answer 1

What's the client of the web service? ASP.NET?

ASP.NET traffic isn't proxied unless you configure ASP.NET to use a proxy. It's possible/likely that the app.config or machine.config changed such that traffic is no longer getting proxied?

You should have a look at this section: http://www.fiddlerbook.com/fiddler/help/hookup.asp#Q-DOTNET

Answer 2

If you want to view the http traffic between your web site and your web service on your development machine, and don't want to change your machine.config.

One easy solution is to change the Application Pool Identity of your web site to use your own credentials of the current logged on user. This means that your web site will adopt your proxy settings and will now redirect to Fiddler.

Answer 3

Make sure the web service you are calling (from IE) is not http://localhost/yourwebservice

Fiddler will not intercept localhost traffic from IE, use http://machinename/yourwebservice instead.

Answer 4

I ran into this issue a week or so ago. Try this page: http://docs.telerik.com/fiddler/Observe-Traffic/Troubleshooting/NoTrafficToLocalhosthttp://www.fiddler2.com/fiddler/help/hookup.asp#Q-LocalTraffic

The ipv4.fiddler was the part that worked for me. Hope this helps.

Answer 5

You're probably using a port other than 80 for these http requests. I remember setting up a reverse proxy to look at WCF requests I was making on my local machine during dev. Here's the documentation: http://www.fiddlertool.com/fiddler/help/reverseproxy.asp

Answer 6

Can you try the following -

1. Try stopping the windows firewall and see what happens
2. try using firefox and redirecting traffic to fiddler and see what happens