Having an issue opening dynamic links in IE9 on Win 7 PC's using Forefront Proxy servers

We have just forced all user PC's to use the internet proxies only and they no longer have direct internet access.  Everything is working fine for everyone but we have come across a few problems with dynamic links from various websites.

We receive emails with links like the one below through email when the user clicks on the link it dose not open.  It looks like any web page link with a "?" in it causes this problem 

https://secure-mail.medibankhealth.com.au/b/l.e?r=medicals%40comany.com.au&n=RlYTkWwn0xLB2BX5wwBv8Q%3D%3D&OWASP_CSRFTOKEN=null

We can see the computer not using the proxy for some reason and trying to go directly to the internet and hitting the firewall which is blocking it.  Not sure why the PC in not using the proxy.pac file?  Even if we copy and past the link into IE9 MOST of the time the link dose not work.

However if a user opens in a separate IE session the below link first then clicks on the problem link from an email it now works but only when the below page is already open on the users PC. 

https://secure-mail.medibankhealth.com.au/b/l.e

The other fix we found is if we set the proxy settings manually with the port in the lower part of the IE settings on the users PC.

The preference is to use the proxy.pac file and would like to find a way to make this work.

 

Hi,

Thank you for the post.

Please refer to this blog:http://blogs.technet.com/b/isablog/archive/2010/11/11/case-sensitivity-of-isa-tmg-generated-proxy-auto-configuration-pac-files.aspx

Regards,

Thanks for the reply I'll check the Case settings in the proxy file, but I'm not sure if this is what the problem is.

Checked and we don't have any caps in our domain's listed in the proxy file.

We did some logs with Wireshark and can see the PC request the PAC file but then dose not use it and request the DNS IP from the internal DNS server and tries to connect directly through the internet no through the proxy???   

Hi,

does that use internal DNS for all request or for particular ones?

The DNS server the clients connect to dose both Internal and has forwarders to the internet. 

Just a FYI found the issue

I have the following line in the PAC script

shExpMatch(url,"*company.com.au*") so this stops the proxy being used as the above address has an email with address with the company name in it "medicals%40comany.com.au"

Thanks for the few suggestions it was forcing me to keep looking at the PAC file.