Fiddler not sniffing SOAP traffic from ASP.NET website

JohnIdol picture JohnIdol · May 6, 2010 · Viewed 28.3k times · Source

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

EricLaw picture EricLaw · May 7, 2010

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