I have a IIS 7.5 on Windows2008, hosting a couple of dozen of sites.

Two sites use HTTPS, we call them www.site1.com and www.site2.com

Now the problem is that if I (for any reason) browse to https://www.site3.com the connection is not dropped as expected (by me) but the browser shows the alert of unsecure content, because the domain doesn't match the certificate.

I don't know how to avoid this behavior and I wonder if it's even solvable.

  • Sorry first of all what do you mean by connection is not dropped by me. i am assuming you have setup the correct host header for your sites. Next question is how did you setup your bindings? – Hamed Jan 21 '14 at 15:03
  • The binding of all sites are on port 80, except for two sites that have both 80 and 443. So, I'd expect that calling site3.com the connection was dropped, because www.site3.com doesn't have a binding on port 443. – Darko Romanov Jan 21 '14 at 15:06
  • Do site2.com and site3.com resolve to the same IP? – Nathan C Jan 21 '14 at 16:08
  • @NathanC yes, all sites have same IP. – Darko Romanov Jan 21 '14 at 16:31
  • 1
    See stackoverflow.com/questions/5006714/… ...this is exactly your issue. – Nathan C Jan 21 '14 at 16:32

IIS will send the traffic for a particular IP address to the site that is configured for that IP using port 443. SSL or HTTPS requires 1 IP per address (excluding wildcards). So if you have the IP of bound to site1.com on 443 and site2.com on all IPs, then when you browse to https://site2.com you are still calling the same IP address regardless of the host headers, IIS will send you to site1 and throw the certificate warning.

To prevent that behavior, you need another IP for site2.com and bind each site to those IPs in IIS.


1.click and open the registry editor tool.

2.In the editor, place the following registry key as follows:

HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0.

3.right click on the SSL 2.0 then choose new and then click key option.

4.name the new folder server.

5.Inside the Server folder, click the Edit menu, select New, and click DWORD (32-bit) Value.

  1. Enter Enabledas the name and hit Enter.

8.Ensure that it shows 0×00000000 (0) under the Data column (it should by default).

  1. Restart the system

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