How can I create a certificate using makecert
with a 'Subject Alternative Name' field ?
You can add some fields eg, 'Enhanced Key Usage' with the -eku option and I've tried the -san option but makecert doesn't like it.
This is a self-signed certificate so any method that uses IIS to create something to send off to a CA won't be appropriate.
Makecert doesn't appear to support SANs so I created a certificate with SANs for use with IIS using OpenSSL. Check out my post about it.
http://andyarismendi.blogspot.com/2011/09/creating-certificates-with-sans-using.html
An even easier way is to use the New-SelfSignedCertificate PowerShell commandlet, which includes a SAN by default. In a single command you can create the certificate and add it to the store.
New-SelfSignedCertificate -DnsName localhost -CertStoreLocation cert:\LocalMachine\My
Note that you need to run PowerShell as an administrator.
Update
The certificate generated using the below makecert
method does not work reliably in all browsers, because it does not actually generate a "Subject Alternative Name".
If you examine the certificate you will see that it does not actually have a Subject Alternative Name
field, but instead specifies multiple CN
in the Subject
field.
E.g.
Subject:
CN = blah.foo.corp
CN = blah
Whereas a real "SAN" cert would have something like:
Subject Alternative Name:
DNS Name=blah.foo.corp
DNS Name=blah
To understand the differences and history between the "Subject" field with "Common Name" and the "Subject Alternative Name" field, I recommend reading The (soon to be) not-so Common Name.
So it appears that makecert
cannot be used to generate a true "SAN" cert, and you will need to use other tools, such as openssl
.
Original Answer:
At least with the version of makecert
that comes with Visual Studio 2012, you can specify multiple subjects, simply by specifying a comma separated list -n "CN=domain1, CN=domain2"
E.g. (from the technet blog Makecert.exe SAN and Wildcard certificate)
makecert -r -pe -n "CN=*.fabrikam.com, CN=*.contoso.com" -b 01/01/2010 -e 01/01/2100 -eku 1.3.6.1.5.5.7.3.1,1.3.6.1.5.5.7.3.2,1.3.6.1.5.5.7.3.3,1.3.6.1.5.5.7.3.4 -ss my -sr localMachine -sky exchange -sp "Microsoft RSA SChannel Cryptographic Provider" -sy 12 -len 2048