Office365 Outlook Web Access through limited internet


        I am trying to get Office365 OWA to work through our proxy that only allows certain sites. I have added all the IPs from Microsoft in my proxy to communicate with office365. I can log in to:, but when I click on Outlook the page will not display and says http/forbidden. I was wondering is it possible to allow OWA through my proxy with the Microsoft Ips for 365. Word, Excel, opens fine.

Thank you,
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There is List from Microsoft that needs to be allowed for Office 365.

Please have a look in this

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FRANK EGGLESTONAuthor Commented:
Hi I added all the IPs on the site. But one line in the beginning of the article says "Web clients such as the Office 365 admin portal or Outlook Web App won’t be able to authenticate."

Does this mean OWA will not work through the proxy because it has trouble authenticating?

Thanks a bunch
Not sure which one you referring as "Web clients such as the Office 365 admin portal or Outlook Web App won’t be able to authenticate." Could you post the screenshot ?

Office 365 should work through the proxy too. You just need to make sure your proxy server has allowed the sites required for office 365.

Will you be able to check your proxy server logs ?

Which proxy server you are using ?
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FRANK EGGLESTONAuthor Commented:

The Microsoft info,

We are using Cent OS 5.4 , Squid 2.6 (21)

I'll have to ask the network guys for the Squid logs. I will post as soon as it is available.

FRANK EGGLESTONAuthor Commented:
I figured out what my proxy was missing!

http_access allow Safe_ports

After inputting this line into the squid.conf, we were able to access OWA through our proxy that allows limited access.

Thank you for your assistance
FRANK EGGLESTONAuthor Commented:
Correction I allowed:

http_access allow SSL_ports

and the corresponding port ACL:
acl SSL_ports port 443
Ok . Glad that issue is resolved .
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