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I have 3 websites: aaa.my-domain.com, bbb.my-domain.com and ccc.my-domain.com all using a single wildcard certificate *.my-domain.com on IIS 7.5 Windows Server 2008R2 64-bit. That certificate expires in a month and I have a new wildcard certificate *.my-domain.com on my server ready.

I want all those domains to use the new wildcard certificate without noticeable downtime.

I tried the usual through the UI starting with replacing the certificate for aaa.my-domain.com: edit site bindings window in IIS 7.5

But when I press OK, I get the following error:

--------------------------- Edit Site Binding ---------------------------

At least one other site is using the same HTTPS binding and the binding is configured with a different certificate. Are you sure that you want to reuse this HTTPS binding and reassign the other site or sites to use the new certificate?

--------------------------- Yes No ---------------------------

When I click Yes, I get the following message:

--------------------------- Edit Site Binding ---------------------------

The certificate associated with this binding is also assigned to another site's binding. Editing this binding will cause the HTTPS binding of the other site to be unusable. Do you still want to continue?

--------------------------- Yes No ---------------------------

This message tells me that https://bbb.my-domain.com and https://ccc.my-domain.com will become unusable. And I will have downtime for those at least until I'm done replacing the certificate for those 2 domains too, right?

I was thinking that there must be a smarter way of doing this. Possibly through the command line that replaces the wildcard certificate with a new one for all website at once. I couldn't find any resources online as to how to do that. Any ideas?

Sites related to wildcard and binding:

Sites related to binding certificates from the command line:

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@Andrew-Schulman No thanks for changing the text to example.com without changing the images that go with the text. You could have pointed out the me about RFC 2606. Now the question is less clear because the image doesn't stroke with the text. –  Chris Jul 12 '14 at 11:31
Hm, you're right. Sorry about that. Reverted. –  Andrew Schulman Jul 12 '14 at 12:52

1 Answer 1

up vote 4 down vote accepted

The context of the answer is that IIS 7 doesn't actually care about the certificate binding. IIS 7 only ties websites to one or more sockets. Each socket being a combination of IP + port. Source: IIS7 add certificate to site from command line

So, what we want to do is do certificate re-binding on the OS layer. The OS layer takes control of the SSL part, so you use netsh to associate a certificate with a particular socket. This is done through netsh using netsh http add sslcert.

When we bind a (new) certificate to a socket (ip + port), all sites using that socket will use the new certificate.

The command to bind a certificate to a socket is: netsh http add sslcert ipport= certhash=1234567890123456789012345678901234567890 appid={12345678-1234-1234-1234-999999999999}

How to

This part explains how to proceed step-by-step. It assumes you have some websites (aaa.my-domain.com, bbb.my-domain.com) running a *.my-domain.com certificate that is about to expire. You already have a new certificate that you already installed on the server but not yet applied to the websites on IIS.

First, we need to find out 2 things. The new certhash and the appid.

  • certhash Specifies the SHA hash of the certificate. This hash is 20 bytes long and specified as a hexadecimal string.
  • appid Specifies the GUID to identify the owning application, which is IIS itself.

Find the certhash

Execute the certutil command to get all certificates on the machine:

certutil -store My

I need not all information so I do:

certutil -store My | findstr /R "sha1 my-domain.com ===="

Among the output is:

================ Certificate 5 ================ Subject: CN=*.my-domain.com, OU=PositiveSSL Wildcard, OU=Domain Control Validated Cert Hash(sha1): 12 34 56 78 90 12 34 56 78 90 12 34 56 78 90 12 34 56 78 90

1234567890123456789012345678901234567890 is the certhash we were looking for. it's the Cert Hash(sha1) without the spaces.

Find the appid

Let's start of by looking at all certificate-socket bindings:

netsh http show sslcert

Or one socket in particular

netsh http show sslcert ipport=


SSL Certificate bindings: ---------------------- IP:port : Certificate Hash : 1234567890123456789012345678901234567890 Application ID : {12345678-1234-1234-1234-123456789012} Certificate Store Name : MY Verify Client Certificate Revocation : Enabled Verify Revocation Using Cached Client Certificate Only : Disabled Usage Check : Enabled Revocation Freshness Time : 0 URL Retrieval Timeout : 0 Ctl Identifier : (null) Ctl Store Name : (null) DS Mapper Usage : Disabled Negotiate Client Certificate : Disabled

{12345678-1234-1234-1234-123456789012} is the appid we were looking for. It's the Application ID of IIS itself

bind a (new) certificate to a socket

Open a command prompt and run it as a administrator. If you don't run it as administrator, you'll get an error like: "The requested operation requires elevation (Run as administrator)."

First remove the current certificate-socket binding using this command

netsh http delete sslcert ipport=

You should get:

SSL Certificate successfully deleted

Then use this command (found here) to add the new certificate-socket binding:

netsh http add sslcert ipport= certhash=1234567890123456789012345678901234567890 appid={12345678-1234-1234-1234-123456789012}

(use the certhash and appid that you found earlier)

SSL Certificate successfully added

DONE. You just replaced the certificate of all websites that are binded to this IP + port (socket).

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