System.Net defaultProxy section in web.config

  • Thread starter Thread starter Sam Attridge
  • Start date Start date
S

Sam Attridge

Hello!

I'm seeing a very strange issue on our live platform that consists of four
webserver Windows Server 2003 boxes sitting in a cluster behind an ISA server
cluster. They are all running IIS 6. We have the need for webservice
requests to be made from a .Net 2.0 webapp to the outside world so we have
utilised the 'defaultProxy' configuration section to specify a proxy for
outgoing requests as below:

<system.net>
<defaultProxy>
<proxy proxyaddress="http://cache.mydomain.co.uk:8080"
bypassonlocal="true" />
<bypasslist>
<add address="monkey.mydomain.com" />
<add address="www.mydomain.com" />
<add address="192.168.0.1" />
</bypasslist>
</defaultProxy>
</system.net>

As you can see, we have also specified a bypasslist so that webservice calls
within our webapp that makes a call to a different website on the same server
don't go through the proxy.

This works for the most part on our live system throughout the day but as
the system comes under heavy load, the webservice requests that should bypass
the proxy suddenly start to be routed through the proxy and will remain this
way until an App Pool recycle is done. At this point, it goes back to how it
should work. This happens on all four servers; generally within a few
minutes of eachother.

I've outputted the proxy settings that are being used during the webservice
call and I can see the bypasslist when everything is working correctly and
the 'bypassed' property is 'true' for the local webservice url. However,
when it goes wrong I can no longer see the bypasslist and the bypassed
property is 'false'. The proxyaddress property remains the same all the time.

Not sure if it's a symptom or not but the only other very strange thing is
that, when it's working correctly, the proxy object can be cast back to a
WebProxyWrapper class but, when it stops working, it can be cast back to a
WebProxy class.

Has anyone else experienced this issue or does anyone know why this might be
happening?

Thanks in advance for any help.
 
Seems our live servers don't have the most recent update to 3.5 framework SP1
(http://support.microsoft.com/kb/951847) which identifies an issue with the
HttpWebRequest object not being able to maintain a persistent connection to a
proxy. I'm going to organise getting this applied to our live servers and
will post the outcome.
 
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