[SOLVED] Disable 'mixed content' security warning popup dialog box

5/7/2011 13:28 lsz

PROBLEM

Navigation theough to an email by clicking on an email in the email list in Google Mail is interrupted by a security warning popup dialog box:

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Security Warning

Do you want to view only the webpage content that was delivered securely?

(IE8) This webpage contains content that will not be delivered using a secure HTTPS connection, which could compromise the security of the entire webpage

(IE7) This page contains both secure and nonsecure items. Do you want to display the non secure items

More Info Yes No

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The 'More Info' button provides no clue as to what settings need to be changed in order to suppress this warning, nor information specific to the user's specific configuraton.

Googling this issue shows it to be the "mixed content" problem with Internet Explorer. The canonical solution -- to navigate to Tools | Internet Optionis | Security | Custom level and changing Miscellaneous | Display mixed content from 'Prompt' to 'Disable' -- does not work in this case.

Site on which the link is being attempted is connected via https and is listed specifically in "Trusted Sites", yet is not trusted ('trust' is evidently not transitive) (site is https://mail.google.com/mail/) Only some email links exhibit this behavior. mail.google.com has a valid security certificate.

SOLUTION

The solution here is a bit different than what I have seen in all other posts on this issue. This solution calls for a change in a specific security zone.

Apply the canonical solution above to the 'Local intranet' zone. Applying it to 'Internet' or 'Trusted sites' zones has no effect.

DISCUSSION

This problem occurred when I attempted to view the Doonsbury Daily Alert email link 'list' in my Goole Mail list of email.

There are four 'zones' in Internet options | Security: Internet, Local intranet, Trusted sites and Restricted sites. Even though Google Mail is identified as a trusted site and is accessed via SSL (https://mail.google.com/mail), the security prompt of 'mixed content' is not disabled by the setting in either 'Internet' or 'Trusted sites' zones. Only by disabling it in 'Locsl intranet' does this work to disable this annoying popup.

Furthermore, this popup only occurs when the user chooses to navigate to the email via the control-left mouse click to open up a new window. If the user simply left-clicks on the link to the email, the popup does not occur.

To review: the 'mixed content' by default is set to 'prompt' (Miscellaneous | Display mixed content) in all the 'Internet', 'Intranet' and 'Trusted sites' zones. When the link to the email is attempted directly with left-mouse click, the email displays OK. When the link is attempted with a control-left mouse click to open a new windows, the popup security warning is displayed.

When this 'mixed content' flag is set to 'Enable' in the 'Intranet' zone the security warning popup dialog box is finally suppressed.

The workstation in question is on a LAN workgroup with three other workstations, accessing the internet through a router on the LAN. This may have something to do with having to invoke the "Local intranet' zone, but why is certainly not clear.

-- Roy Zider

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